452 S. F. Peckham — The Pitch Lake of Trinidad. 



beds of sand, gravel, and laminated loam or clay, are looked upon 

 as the pi'oduction of land-ice, so long will these enthusiastic glacial- 

 ists fail to arrive at intelligible conclusions regarding the physical 

 conditions of the Glacial period. Is it not much more rational 

 to suppose that three superimposed deposits, differing in composi- 

 tion and structure from each other, should have been formed under 

 three different sets of conditions rather than under one and the 

 same or similar ? And in the case of the Aberdeenshire deposits 

 surely we have a very evident succession of conditions, such as, in 

 brief: 1st, general land glaciation ; 2nd, submergence in sea-waters, 

 during which the rivers bi'ought down sand and gravel from the 

 adjoining emergent lands to be taken up and distributed over the 

 sea-bed ; and 3rd, continued submergence, with the recurrence of 

 cold conditions, owing to which the snows and glaciers again occu- 

 pied the higher elevations, and the streams charged with glacier 

 mud entered the sea and gave rise to a Eed Clay formation. The 

 Aberdeenshire deiDOsits do not stand alone ; they have their equiva- 

 lents in Lancashire and Cheshire and in Ireland. The fine section on 

 the banks of the Eibble above Preston is identical (mutatis mutandis) 

 with that on the coast of Scotland, and indicates similar widespread 

 conditions in the Glacial period, Mr. Bell denies submergence ; 

 but I am tempted to quote a passage from a letter recently re- 

 ceived from Prof. Prestwich on this subject, which may possibly 

 have some weight with the neo-glacialists.^ He says : " I quite 

 agree with you as to the important submergence in Glacial times 

 which has left such clear evidence in the Cotteswold Hills- and 

 Welsh Mountains. It is surprising to me that the ice-ploughing 

 hypothesis could ever be entertained. Some half century ago it 

 was my good fortune to come across some fossiliferous gravels in 

 the hills (1,120 feet) between Chesterfield and Buxton. Why the 

 simple explanation should ever have been pushed aside in favour 

 of the more fanciful view I cannot understand, unless it be the 

 innate love of chanee." Neither can the writer. 



V. — On the Pitch Lake of Tkinidad. 



By S. F. Peckham. 

 [Continued from the September Ntimler, p. 425.) 



"VTEAE the crest of the ascent to the lake the road divides: one 

 1.1 branch passing to the left and south ascends over the rim of 

 the basin of the lake, and skirting the lake for about a quarter of its 

 circumference passes over the hill to the south-west, as described by 

 Mr. Manross. The right-hand branch follows the flow of the jDitch 

 and enters upon the lake simply by a change of grade from a sharp 

 ascent to a very slight inclination upwards towards the centre of the 

 lake. I was particularly impressed with this fact, and took pains 



1 Dated 25th July, 1895. 



^ On the Jurassic table-land of the Cotteswolds we find round quartzite pebbles, 

 washed out of the New Eed Couglomerate of the Midlands, scattered OA'er the surface 

 up to a level of about 600 feet— a real " I^orthern drift." 



