BT THE PEESIDEXT. 115 



subjects which strike me as being such as would interest the 

 members of the Society, and which lie within easy reach of nearly 

 all of us, especially of those, of course, who have paid any particular 

 attention to the departments of Natural History under which each 

 subject lies. 



In Geology we have had, as I said before, Mr. Lobley's paper on 

 the Chalk, and Professor Morris's paper on the London Basin. Mr, 

 Lobley, in his very interesting paper, gave us some account of the 

 method in which the Chalk had probably been deposited, and you 

 will find in the illustrations of his paper some of those minute 

 organisms which have been washed out of the Chalk placed side by 

 side and compared with other organisms of a similar character 

 which have been dredged up from the deep sea in the course of the 

 expedition of the Challenger. That expedition of the Challanger 

 will, I think, throw a very material amount of light upon the 

 origin, not only of the Chalk, but of various other rocks ; for it is 

 found in the course of their soundings that they have brought up, 

 at the very least, four different kinds of sea-bottom. In shallow 

 water they brought up something, which to all appearance was 

 sand of a greenish colour, but which, after close examination under 

 the microscope, proved to be casts of small animals of the Fora- 

 minifera class, which had been converted into a mixture of flint, 

 clay, and iron, which has this greenish appearance. Chemically it 

 is spoken of as glauconite, or silicate of iron and alumina. This 

 foraminiferal sand is characteristic of some of the beds at the base 

 of the Chalk, what we call the Greensand consisting to some 

 extent of similar fossiKzed organisms converted in the same 

 manner. There is a point which, I think, might very well be 

 investigated by members of this Society, by examination under the 

 microscope, as to whether in the Leighton sands, which are 

 frequently brought into this neighbourhood for building purposes, 

 they could not find some of those organisms which have been con- 

 verted into this peculiar greensand or glauconite. But at greater 

 depths the soundings have brought up a white ooze, consisting 

 mainly of the same shells, but mixed also wdth the spikes of very 

 minute organisms which seem to live on the surface of the sea, — 

 little animals like sea-urchins, with spines all over them ; the 

 spines of which fall to the bottom of the sea, and fill up the spaces 

 left by the larger, but still very minute organisms. Similar 

 remains are to be found in the Chalk, and there again is a subject 

 that some of our microscopists might take in hand. But going to 



