STODDARTj ON MICRO-GEOLOGY. 149 



lie iu such profusion that they actually divide strata from 

 strata with layers of their valves. In these early deposits we 

 find scales, spines and teeth of fishes, whose markings are so 

 fine that they w^ould entirely escape notice without the micro- 

 scope. Then, again, there is the compound eye of the mar- 

 vellous trilohite, wath its thousands of facettes, each capable 

 of transmitting a faithful picture of an object to its possessor. 

 In the succeeding era (the Devonian) we find abundance of 

 microscopic work in the remains of zoophytes many feet 

 thick, and so beautifully preserved that they are, when 

 polished, among our choicest objects. The microscopist here 

 will delight in the delicate Fenestella, the extraordinary scales 

 of the Holoptychius and Cephalaspis, The spine of the 

 Cheiracanthus, and bony plates and teeth of the Coccosteus, 

 make very good sections. 



The Carboniferous deposits are of much greater interest to 

 the microscopist. In almost every part of tliis system we 

 have numerous and astonishing examples of what changes a 

 little creature may affect in the surface of our globe, and that 

 creature, of so lowly an organization that it has but few of 

 the attributes of an animal. Ranges of solid rock, many 

 miles in length and depth, owe their existence to the lime- 

 eliminating power of a little coral. The beds exhibited by 

 the fine section at Clifton are most excellent localities from 

 which very rare specimens may be abundantly obtained. From 

 it are collected ISIillepores, Madrepores, Seriatopores, Spongi- 

 olites and Polyzoa of the most varied shapes and forms. In 

 the Oolitic beds of limestone, ten genera of Foraminifera have 

 been found. It is at the base of the Clifton beds that the author 

 noticed the most extraordinary deposit of limestone ever known 

 to the geologist. It is described in the 'Ann. Nat. Hist.,' Dec. 

 1860, and consists of a^ rock twelve feet thick, every pound 

 by weight of which contains more than two millions of perfect 

 Microzoa, Cytheridae, Gasteropods, and very beautiful cylin- 

 driform Polyzoa, the latter being so perfectly preserved as to 

 show the cells and thin apertures. Coal is another well-known 

 and striking instance of what may be deduced from micro- 

 scopic observations. On looking at a bit of the substance, 

 especially that from Derbyshire, its woody structure, with its 

 beautifully preserved cells, will be easily recognised. On exa- 

 mining it more closely, you will notice that between the fibres 

 is a total absence of interposed vessels, but instead, small 

 glandular dots are arranged in one or more rows. From this 

 peculiarity we at once conclude that the tree was a conifer, 

 and, from the disposition of the dots, that it belonged to the 

 genus Araucaria Then on looking carefullv over the beds in 



