SALTER — A CHRISTMAS LECTURE ON COAL, 



181 



For with, these shells, and attached to the plants that lie among, 

 and above, and beneath the shell-beds, is fonnd abundantly a little 

 sea-worm, or rather the spiral case of a sea-worm 

 # & (Spirorbis, fig. 4), which is as well known now 

 npon sea-wrack and kelp, as it was upon floating 

 Yig carfonariu$ Us l eaves an( ^ plant-stems in the coal-period. It is 

 called Sp. carbonarius from its habitation in the coal. 



And there were sea-crabs — not, it is true, like English ones — but 

 like the king-crab (lAmulus) of American waters. And shrimps 

 though rare, were not quite absent. And sharks swam in the water ; 

 for we find their teeth and fin-bones. And other strange uncouth 

 fish, more like the bony pike of America than aught else. This is a 

 freshwater fish, and tells rather against my opinion ; but all I can 

 say is, that if the coal-fishes were not saltwater^fishes, they had no 

 business among saltwater shells and Crustacea, and they must take 

 the consequences. 



But how reconcile saltwater and its inhabitants with lofty trees, 

 and a thick jungle, and delicate ferns ; and colonies of insects, and 

 spiders, and scorpions, and lizards ? 



No doubt this is a difficulty. Most authors who have written on 

 the coal have taken it for granted that it must have been formed in 

 mighty swamps at the mouths of rivers, with only frequent access of 

 the sea ; with much dry land in the neighbourhood to supply the 

 ferns and firwood, and permit the growth of a thick underwood such 

 as certainly must have formed the coal. 



But others, and amongst these I must name Prof. Henry Rogers 

 of America, and our own Mr. Binney chief*, have not shrunk from 

 the supposition that the Sigillaria grew on the sea-bed itself. 



" Only one particular process," says Prof. Rogers, " promises to 

 explain the occurrence of these thin and uniform sheets of material, 

 of which the thickness is often less than a foot, while their super- 

 ficial area is many hundred square miles. I cannot conceive any 

 state of the surface but that in which the margin of the sea was 

 occupied by vast marine savannahs of some peat-forming plant, grow- 

 ing half-immersed on a horizontal plane, fringed and interspersed 

 with forests of trees, shedding their leaves upon the marsh. 

 Such are the only circumstances under which I can imagine these 

 regularly parallel, thin, widely-extended sheets of carbonaceous 

 matter could have been accumulated." 



The smooth surface of the underclay formed a fit nidus for the 

 young plants, and as the deposit went on, they struck their roots far 

 and wide into it, and grew to their full stature. These trees formed 

 the bulk of the coal-forest. The interstices were filled with the 

 reedy plants, Asterophyllites, Calamites, and sedges, with many a 

 Lepidodendron and coniferous tree ; and as the decaying leaves and 



* Trans, of the Association of American Geologists and Naturalists, 1842 ; p. 433. 

 Binney, Manch. Geol. Trans, vol. i., p. 172, 1840. 



