317 



By A. J. Jukes- Beowne, B.A., F.G.S. 



Part I. — Description of the Strata and their Peculiarities 

 of Structure. 



PAPER on the geology of any town or district is often a 

 w very dry-as-dust affair, consisting chiefly of descriptions o£ 

 rocks, with a scattering of technical terms and names of fossils that 

 convey little meaning to ordinary ears. That kind of paper is not 

 at all suitable for delivery to a general audience, and should only be 

 read to an assembly of geologists. There are, however, certain facts 

 in the geology of any district, and in the structure of its rocks, 

 which may be explained and made interesting to people who have 

 little or no acquaintance with the science of geology. It is these 

 portions of the subject which are dealt with in the first part of this 

 paper, the more technical questions of nomenclature and classification 

 being left to form the second part. 



Professor Huxley once gave a lecture on a piece of Chalk, and 

 found a great deal to say about it, both as to the peculiar structure 

 of the material and as to the manner in which it was made. Some 

 people may imagine they know all about Chalk when they know 

 that it is composed of carbonate of lime, but the microscope tells us 

 that there are as many different kinds of Chalk as there are different 

 kinds of Clay or Sandstone ; it shows us also that the number of tiny 

 fossils and organic remains in a crumb of Chalk is as large as the 

 number of live animals in a drop of pond- water. Some of you may 

 have seen the magnified reflection o£ such a drop of water thrown on 

 a screen by means of the oxyhydrogen lantern, and will remember 

 the lively scene it exhibited. In some pieces of Chalk the remains 

 of minute animals are nearly as numerous, but before entering on 



\* The Society is indebted to Mr. Jukes-Browne's kindness for two-thirds 

 of the cost of the illustrations of his paper. 



z 2 



