100 Horner's Geological Address, 



here I may remark, in passing, that while we, as geologists, 

 have to thank that provincial Government for commencing 

 so useful an undertaking, we have also the satisfaction of 

 feeling convinced that it will be prosecuted with vigour by 

 the present governor, Earl Cathcart, one of our own body, 

 and, as we know, an able and active geologist. This is a 

 section of the same series of coal-measures so carefully ex- 

 amined and described by Mr Lyell,* though with less mi- 

 nuteness of detail as to the lithological characters and dimen- 

 sions of the several beds. The phenomena exhibited in the 

 above sections are not peculiar to them ; they are to a great 

 extent common to all coal-fields, particularly in the higher 

 parts of the carboniferous series. 



Before giving the analyses I have made of these sections 

 I wish to call to your recollection that in both theories it is 

 assumed, that the deposition of the coal-measures took place 

 in the sea. Mr Lyell speaks of the accumulations having 

 taken place in a sea : he says, " It by no means follows that 

 a sea four or five miles deep was filled up with sand and se- 

 diment ; on the contrary, repeated subsidences may have en- 

 abled this enormous accumulation of strata to have taken 

 place in a sea of moderate depth." 



The example from South Wales is a vertical section, t re- 

 presenting the beds as they are known to succeed each 

 other in descending order, the dimensions being the thick- 

 ness of each bed at right angles to the plane of stratification. 

 The coal-measures rest upon carboniferous limestone, in an 

 inclined and somewhat waved stratification ; and although 

 these measurements would vary in difi'erent places, from the 

 swellings and thinnings-out which all strata exhibit more or 

 less when traced to a distance, they are probably not far 

 from the average amount over a large area. 



1. From the top of the highest bed to the limestone, the 

 sum of the measurements amounts to nearly 7000 feet ; that 

 is, the beds must have been originally deposited over each 

 other in horizontal or nearly horizontal stratification to that 

 thickness. 



* " Travels in America," vol. ii., p. 198. 



t No. 1 in the series, illustrating the horizontal section No. 7. 



