Ch. XXI] FOSSILS OF THE LIAS. 327 



entire skeletons of the marine lizards from which they were derived " as 

 if," says Sir H. De la Beche, " the muddy bottom of the sea received 

 small sudden accessions of matter from time to time, covering up the 

 coprolites and other exuviae which had accumulated during the inter- 

 vals."* It is farther stated that, at Lyme Regis, those surfaces only of 

 the coprolites which lay uppermost &t the bottom of the sea have suf- 

 fered partial decay, from the action of water before they were covered 

 and protected by the muddy sediment that has afterwards permanently 

 enveloped them.f 



Numerous specimens of the Calamary, or pen-and-ink fish (Geoteuthis 

 JBollensis, Schuble sp.) have also been met with in the lias at Lyme, with 

 the ink-bags still distended, containing the ink in a dried state, chiefly 

 composed of carbon, and but slightly impregnated with carbcnate of 

 lime. These cephalopoda, therefore, must, like the saurians, have been 

 soon buried in sediment ; for, if long exposed after death, the membrane 

 containing the ink would have decayed.^ 



" As we know that river fish are sometimes stifled, even in their own 

 element, by muddy water during floods, it cannot be doubted that the 

 periodical discharge of large bodies of turbid fresh water into the sea 

 may be still more fatal to marine tribes. In the Principles of Geology 

 I have shown that large quantities of mud and drowned animals have 

 been swept down into the sea by rivers during earthquakes, as in Java, 

 in 1699 ; and that undescribable multitudes of dead fishes have been 

 seen floating on the sea after a discharge of noxious vapors during simi- 

 lar convulsions.§ But, in the intervals between such catastrophes, strata 

 may have accumulated slowly in the sea of the lias, some being formed 

 chiefly of one description of shell, such as ammonites, others of gryphites. 



From the above remarks the reader will infer that the lias is for the 

 most part a marine . deposit. Some members, however, of the series, 

 especially in the lowest part of it, have an estuary character, and must 

 have been formed within the influence of rivers. In Gloucestershire, 

 where there is a good type of the lias of the West of England, it has 

 been divided into an upper mass of shale with a base of marlstone, and a 

 lower series of shales with underlying limestones and shales. We learn 

 from the researches of the Rev. P. B. BrodieJ that in the superior of 

 these two divisions numerous remains of insects and plants have been 

 detected in several places, mingled with marine shells ; but in the infe- 

 rior division similar fossils are still more plentiful. One band, rarely 

 exceeding a foot in thickness, has been named the " insect limestone." It 

 passes upwards into a shale containing Cypris and Estheria, and is 

 charged with the wing-cases of several genera of coleoptera, and with 

 some nearly entire beetles, of which the eyes are preserved. The ner- 

 vures of the wings of neuropterous insects (fig. 419) are beautifully per- 



* Geological Researches, p. 334. 



f Buckland, Bridgew. Treat, p. 307. % Ibid. 



§ See Principles, Index, Lancerote, Graham Island, Calabria. 



|| A history of Fossil Insects, &c. 1846. London. 



