Chap. I.] history of geology. 15 



seen in contact with the fault bounding the field to the West. Mr. 

 Williams proceeds to mention the coal seam at Chanch, and to 

 refute some statements of Mr. Homfray concerning its mode of 

 occurrence. In doing so, however, Mr. Williams may perhaps be 

 in error himself in considering the Chanch seam to be necessarily 

 co-extensive with the ironstone shales, the base of which is stated 

 to be 340 feet higher in the series, and the area covered by 

 which is mentioned. Mr. Williams believed that, " according to a well- 

 known established fact in Geology," the coal underlies the ironstones 

 for " several hundred square miles to the East and North-east." The 

 recent examination, conducted more closely, and altogether under more 

 favorable circumstances than existed at the time of Mr. Williams's 

 survey, has induced the belief that coal seams in the Damuda field 

 generally, and especially in the lower portion of the series, are not con- 

 tinuous equally over large areas. And also that there is considerable 

 probability of the existence of unconformity between the ironstone 

 shales and Lower Damuda rocks, the latter containing the Chanch seam : 

 there is therefore much reason to doubt the correctness of the opinions 

 expressed upon this point. 



The great mass of carbonaceous shales and ironstones receive only 

 a passing notice. The Report proceeds thus :— 



" Having descended through the series of rocks above noted, which 

 " are analogous to the lower coal-measures of England and elsewhere 

 " and rich in both coal and iron mines, a fact which would have 

 " considerable influence on the passing observer and induce him to 

 " suppose that he had arrived at the base of the productive coal- 

 " bearing measures, especially as the sandstones and conglomerates 

 " underlaying them exhibit a close analogy to the millstone grit or 

 " farewell-rock series, in which no coal of any commercial value was 

 " ever found : the beds generally entombed in this part of the carbo- 

 " niferous formation are thin and very inferior in quality, varying in 



