NOTICE. 



In the report^ published in the preceding portion of the present 

 Vohime of these Memoirs (Vol. IV.) ^ drawn up by Mr. H. F. Blanford, 

 the results of a careful and detailed examination of the richly fossiliferous 

 deposits of Trichinopoly and South Arcot^ which belong generally to the 

 Cretaceous period of geologists^ have been given. The present report 

 relates to the remainder of the area included in the same sheet of the 

 Indian Atlas (Sheet No. 79). It is^ purposely^ not so detailed as the 

 former^ a vast portion of the area being composed exclusively of metamor- 

 phic rocksj which neither offer the same variety nor the same interest, as 

 attesting succession of events, as the fossiliferous rocks. On some points, 

 such as the valuable beds of Magnetic Iron ore, fall details are given, 

 but in general only the main features are alluded to. This portion of 

 the country has been mapped almost entirely by Messrs. William King 

 and R. Bruce Foote, who are the joint authors of the report. . 



The sheets of the Indian Atlas, being the only permanent form in 

 which the results of the great surveys of India are published, have been 

 adopted as the maps on \7hich the geological lines fixed during the pro- 

 gress of the Geological Survey of India, should be put before the public. 

 These sheets are, however, of considerable size, and ov/ing to their com- 

 paratively small scale (4 miles to 1 inch) , each sheet represents an area of 

 more than 14,500 square miles. It is obvious that the careful examina- 

 tion of such an area would require a long time, and would, if done in any 

 detail, spread over several years. And therefore, as no sheet can be pub- 

 lished until the examination of the entire area embraced in it has been 

 completed, a considerable time must often elapse before this can be ac- 

 complished. I anticipate that much of this unavoidaljle delay will bo 



