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survey was necessary. Further details were given as to the nature of the rock sections laid bare and the transportation of the shingle; and the main facts were illustrated by photographs and a water-colour sketch of the new inlet formed at Southwold.

[The author's communication was printed in full in the Supplement to the 'East Anglian Daily Times' of September 13, 1895.]

6. Observations on East Anglian Boulder Clay.

By Rev. E. HILL, M.A., F.G.S.

Some personal observations are described, and inferences from them suggested. The present effect of frost on clay shows that the grinding actions of land-ice need not be invoked.

The comparative distributions of Kimmeridge clay and chalk, and also the intimate mixture of chalk-fragments with clay-matrix, are opposed to land-ice

theories.

A partially scratched fragment from the heart of the clay suggests flotation.

The contour line of 300 feet includes little Chalk but much Boulder Clay, which is said to reach altitudes in the Midlands higher than any Chalk. This points to

alteration in relative as well as absolute levels.

A resemblance to some artificial clays suggests that the Boulder Clay may have been deposited rather rapidly. If so, the absence of life is no difficulty; neither is the alleged absence of stratification.

These inferences would all agree with deposition in water, and with a tilt of the earth-surface.

7. Indications of Ice-raft Action through Glacial Times.

By Rev. E. HILL, M.A., F.G.S.

Over post-Glacial gravels lie sheets of Boulder Clay. In the Boulder Clay scratched stones, contorted sands at Sudbury, gravel and chalk at Claydon, the Roslyn Hill chalk at Ely, are best explained by transportation and dropping. In mid-Glacial sands, between Gorleston and Lowestoft, portions of Boulder Clay occur in the midst of the sands, as if dropped by ice-rafts. A majority of writers on the Cromer cliff's attribute the chalk masses in the Contorted Drift to icerafts.

Thus through Glacial times are indications of ice-raft action.

8. On Traces of an Ancient Watercourse.
By Rev. E. HILL, M.A., F.G.S.

A peculiar gravel occurring along a line of seven miles indicates an ancient brook. Though its hollow is in Boulder Clay, yet patches of like clay overlie the gravel, and probably have been carried down on to it in a frozen state. nature of the gravel agrees with its having been formed on land little elevated.

The

9. Further Notes on the Arctic and Palæolithic Deposits at Hoxne. By CLEMENT REID, F.L.S., F.G.S., and H. N. RIDLEY, M.A., F.L.S. The exact relations of the deposit with Arctic plants discovered in 1888 (see British Association Report, p. 674) to the Paleolithic deposits and to the Boulder Clay in the same pit being still uncertain, the authors returned last spring, intending to pump out the water and examine the beds in place. This they were unable to do owing to the water being required for the brickyard; but by means of borings

and an examination of the deposits above the water level they ascertained that the succession was probably as follows:

Gravelly surface soil

Brickearth: towards the base Valvata piscinalis,
cyprids, bones of ox, horse, elephant (?), and
Paleolithic implements

Sandy gravel, sometimes carbonaceous, with flint
flakes

Peaty clay, with leaves of Arctic plants (?)

Lignite, with wood of yew, oak (?), white birch, and
seeds of cornel, &c.

Green calcareous clay, with fish, Valvata piscinalis,
Bythinia tentaculata, cyprids, Ranunculus repens,
Carex
Boulder clay.

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The authors suggest the appointment of a committee to continue this work, as Hoxne is apparently the best locality in the Eastern Counties for ascertaining the relation of Palaeolithic man to the Glacial epoch. The seeming occurrence of a temperate flora between the morainic deposits and the clays with Arctic plants should also be investigated and decided beyond question.

10. Some Suffolk Well-sections. By W. WHITAKER, F.R.S.
Ordered to be printed in extenso.-See Reports, p. 436.

FRIDAY, SEPTEMBER 13.

The following Papers and Reports were read :—

1. On Pitch Glaciers or Poissiers. By Professor W. J. SOLLAS, D.Sc., F.R.S.

Pitch and the ice of glaciers strikingly resemble each other in behaving as solids and liquids, according to their manner of treatment. On the sudden application of force they break like brittle material, but yield like fluids when subjected to gradual pull or pressure. Hence it is possible to employ pitch in the construction of working models of glaciers in order to obtain an insight into those internal movements of actual glaciers which are beyond the reach of direct observation. The study of glacial deposits has shown that many erratic boulders were transported during the Glacial period upwards from lower to higher levels, and left stranded on the flanks of mountains some hundreds of feet above their source. This standing difficulty in the way of physical thecries of glacier movement has been explained by the study of pitch models, which show that the lower layers of material on approaching an obstacle are carried upwards in an ascending current. The inference, which is confirmed by other kinds of observation, is that similar movements take place in actual glaciers. Further, a glacier sometimes overrides its terminal moraine without disturbing it; and in one experiment this was exemplified, for pitch flowed for several months over a ridge of loose material without removing a particle cf it. A remark made by Professor Fitzgerald, to the effect that viscosity seemed merely to retard, and not to alter, the nature of the movement in the cases described led the author to experiment with less viscous material, such as Canada balsam and glycerine, and with concordant results. A trough containing Canada balsam flowing upwards over an obstacle under its own head of pressure was shown by the lantern projected on the screen.

A raised model of Ireland has been constructed, and the directions of icemovement, as determined by the Rev. Maxwell Close, indicated upon it by

arrows.

On allowing water streaked with colouring matter to flow over it from two areas, supposed to represent the great gathering grounds of snow of the Glacial period, the water had taken paths, as shown by coloured streaks, corresponding to those taken by the ice, as shown by the arrows.

2. Notes on the Cromer Excursion. By CLEMENT REID, F.G.S.

3 On the Tertiary Lacustrine Formations of North America.
By W. B. SCOTT.

The early French explorers in the western parts of North America discovered certain large areas of extraordinarily broken and difficult country which they called mauvaises terres à traverser -a term which has been translated and shortened into the modern phrase 'bad lands.' Geological examination soon showed that these areas were covered with fresh-water deposits of Tertiary age, and that they represented a series of great lakes in which were entombed a vast number of representatives of the vertebrate faunas which successively occupied the country.

I. (1) The most ancient of these formations is the Puerco, which overlies with apparent conformity the Cretaceous. This rather small lake occupies parts of Southern Colorado and North-western New Mexico. (2) The Wasatch succeeds after an interval and was much larger: it extends from New Mexico into Northern Wyoming. At least two contemporaneous lakes represent this horizon, and at the south its strata lie upon the Puerco. (3) The Bridger is indicated by a much smaller series of lakes, in Wyoming, Utah, and Colorado, which seem to have been successive rather than contemporaneous, and has been divided into three stages: (a) Wind River, (b) Bridger, (c) Washakie. The Wasatch beds pass under the Bridger at very many points. (4) Extensive orographic movements followed the Bridger stage and led to the formation of a new lake basin in Northern Utah, overlying the Bridger-the Uinta. Osborn has shown that two distinctly marked horizons occur within the limits of the Uinta. (5) The Uinta was the last of the great bodies of fresh water in the region to the west of the main chain of the Rocky Mountains. The movements now affected the Great Plains region, and an enormous lake was developed which extended along the eastern front of the mountains from Nebraska into North Dakota, together with a second basin in Canada. This is the White River formation, which is plainly subdivisible into three horizons-the Titanotherium, Oreodon, and Protoceras beds. (6) This was followed by the John Day, which is mostly confined to Oregon, but a second very small basin occurs also in Central Montana. (7) A considerable hiatus separates the John Day from the overlying Loup Fork, which is by far the most extensive of all the Tertiary lakes, and covers nearly all the Plains region, from South Dakota far into Mexico. It is not yet certain whether this was one vast body of water or a connected series of lakes. Independent basins occur in Montana, Nevada, and Oregon. In these the Loup Fork overlies the John Day unconformably, as farther east it overlies the White River. The Loup Fork falls naturally into three horizons, separated both by their faunas and more or less marked unconformities: (a) Deep River, only in Montana; (b) Nebraska, the principal area of the Plains region; (c) Palo Duro, known in Kansas, but principally developed in Texas. (8) In the Indian territory and Texas, in places overlying the Palo Duro, occurs the Blanco, the boundaries of which have not been traced as yet. (9) Occupying the surface of most of the Great Plains region are the uncompacted and obscurely stratified Equus beds, which rest unconformably upon all other formations of the region, from the Cretaceous to the Pliocene.

II. The Lacustrine beds have for the most part retained their horizontal position, only rarely being tilted. They are composed of felspathic muds, clays, sands, and conglomerates, generally cemented by some calcareous compound, and

their hardness is, speaking broadly, proportionate to their antiquity. The removal of the soluble cement by rain-water causes the rock to crumble, and the bad lands are examples of atmospheric erosion on a very grand scale. This erosion is extremely slow, the soil shedding the rain almost completely, but land-slips and snow avalanches in the spring frequently expose fresh surfaces of rock. The John Day beds are largely composed of the glassy particles of volcanic ash and the whole is overlaid by late basaltic flows.

In the lake basins the old shore lines and deltas may frequently be traced, and their fossil contents sometimes afford interesting hints as to the habitat of the land animals.

Climatic changes are registered in the alteration of the floras, as in the gradual disappearance of the palms from the central latitudes and in the diminution in the abundance and variety of the reptiles. For example, large crocodiles are exceedingly common in all the Eocene formations, including the Uinta, but in the succeeding White River only a few dwarf forms have been found.

III. The correlation of formations in different continents is a difficult matter, but least so, perhaps, in the case of lacustrine beds in connected areas. The Old and New Worlds were certainly so connected during much, if not all, of Tertiary time, and there is always a certain proportion of land mammals common to the two continents. The natural and sharply marked lines of division are, however, not the same, and were the American formations arranged without reference to those of any other continent, a system very different from the European would result. Thus the Puerco would form one group; the Wasatch a second; the Bridger, White River, and John Day a third; the Loup Fork and Blanco a fourth; and the Equus beds a fifth.

The European system is, however, the standard, and must be employed, and even in this way some very close correspondences may be noted. Thus, the Puerco is somewhat older than the Ceruaysian, while the Wasatch is the exact equivalent of the Suessonian. The Bridger is Middle Eocene (Parisian or Lutetian), and the Uinta in a general way corresponds to the Paris gypsum. The White River is Oligocene (Ronzon), and much misunderstanding has come from calling it Miocene. The John Day may be placed in the Lower Miocene, though it is somewhat older than the beds at St. Gérand-le-Puy, and follows the White River epoch with hardly a break.

None of the American lacustrines is referable to the Middle Miocene. The Loup Fork is Upper Miocene, the Deep River division corresponding almost exactly to the beds of Sausan and Steinheim, while the Palo Duro division is perhaps already basal Pliocene. The fauna of the Blanco series is not yet sufficiently well known for exact correlation, though there can be no doubt that it is Pliocene.

The Equus beds are distinctly Pleistocene, though it still remains to trace their relations to the Drift and to determine whether they are pre-Glacial or Glacial.

4. The Glacial Age in Tropical America. By R. BLAKE WHITE.

The deposits described by the author cover almost the whole of the Republic of Colombia, extending from 12° N. lat. nearly to the Equator, and from the summits and plateaux of the Andes at 10,000 and 12,000 feet down to the plains, valleys, and littorals of the Atlantic and Pacific Oceans. The Glacial age corresponded, in his opinion, with that of greatest volcanic activity. He speaks of moraines from 2,000 to 3,000 feet thick, accumulation of boulders, erratics of enormous size, and a peculiar loess on the high lands, the last containing bipyramidal crystals of quartz supposed to have been formed in situ. Great denudation followed the melting of the ice, and the auriferous deposits of the country belong to this or to the Glacial age. The author considers that a decrease in temperature enough to bring the snow line from 2,000 to 3,000 feet lower than it is at present would account for the phenomena which he describes. This might be brought about by a diminution of the amount of carbonic acid in the atmosphere,

producing rarefaction. He concludes by urging geologists to investigate a country which offers such a promising field, and does not present to the traveller any difficulties of importance.

5. On pre-Glacial Valleys in Northamptonshire. By BEEBY THOMPSON, F.C.S., F.G.S.

The paper refers to the pretty general belief that the larger physiographical features of this country were developed before the Glacial period, and that many of the present river valleys are of pre-Glacial age; and remarks that, if so, they were more or less completely choked with boulder clay during the Glacial period.

Where a valley got completely filled up it would, perhaps, in many cases be easier for the ordinary drainage to cut out a new valley than to remove the infilling of an old one, where the initiative for a new valley had been given by superficial streams due to melting ice. So at the close of the Glacial period, although the main drainage of a district must take approximately the same direction that it did before it, the tributary streams would seldom accurately follow their old lines on having, as it were, a fresh start under somewhat different circumstances. Compromises would, no doubt, frequently result.

Bearing these matters in mind, we should be prepared to find

1. New valleys without drift, and filled-up old ones near at hand.

2. Valleys with one side drift and the other the normal rocks of the district.

3. Valleys still containing much drift, with the streams running over or

through it.

4. Valleys in which only the coarser material of the drift is left in the form of river gravel.

Illustrations of each of the four cases enumerated are given, all from Northamp

tonshire.

The author suggests that his explanation of some isolated patches of boulder clay near to Northampton may prove to be of more general application than previously suspected.

6. Notes on some Tarns near Snowdon. By W. W. WATTS, M.A., F.G.S.

During a recent visit to Snowdon, the writer has taken the opportunity of examining a few of the tarns in its immediate vicinity. These include the two small lakes in Cwm Glas, Glaslyn, and Llyn Llydaw.

In the hollow of Cwm Glas there are two tiny tarns named Ffynnon Frech and Ffynnon Felen; both lakes drain over a barrier of rock, but in a rainy season the upper one appears to find a second outlet over the long, low col to the East, so that, in this state, it has the two outlets depicted in the 6-inch map. There can be little doubt that this upper lake is a portion of a bending valley dammed at both ends by scree- and stream-débris, and thus compelled to find an escape over the rocky side. The lower lake is certainly confined in a rock basin, as rock occurs at its actual outlet and at every point where any former outlet might have been possible. The lake is, however, so shallow that its occurrence in a basin of rock is perhaps of little consequence.

The neighbouring hollow of Cwm Dyli, as is well known, contains three lakes, the highest being Glaslyn, the next Llyn Llydaw, and the lowest Llyn Teyrn. Glaslyn is bounded on all sides by live rock except at and near its outlet. This exit is over moraine, which, however, is evidently not very deep, for rock makes its appearance just below, and in such a way as to almost compel belief in a complete rock bar. Beside the present course of the effluent stream is a parallel strip

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