1845.] Diluvial and Wave Translation Theories. 241 



ful and entertaining occupation of collecting specimens from the coun- 

 tries they visit." This observation applies particularly to India — 

 the geology of which is so little known — where, it is true, there are no 

 professed geologists attached to our surveys; but where every indivi- 

 dual has the means and ability of adding his mite to the general stock 

 of knowledge, without any serious encroachment on his duties or his 

 pleasures. " Even those who run may read" in the great open book 

 of Nature; and if they read, there is no reason why they should not 

 note, for the benefit of those who have not the opportunity of studying, 

 the same pages.* 



Boulders and erratic Blocks. The term u boulder" has been 

 often misapplied to any loose rounded block of rock lying on a 

 plain, or elsewhere on rocks, or the soil of rocks, of which it ori- 

 ginally formed part. This is not a li boulder" in the geological 

 acceptation of the term, the block being in situ; or not distant from 

 the rocks of which it once formed part. A true boulder is a mass 

 of rock, the corners of which have been rounded, from the size of 

 a man's head to that of a field-officer's tent or a small bungalow, 

 found detached and at a distance from the parent rock of which 

 it once formed part, and resting on rocks generally of a different nature, 

 or imbedded in gravel, clay, or loam. 



Erratic blocks are fragments of rock, with sharp or little blunted 

 corners, found in similar situations as boulders, or what is termed not 

 " in situ," or transported from their native beds. Among the most 

 remarkable erratic blocks in the world are the angular blocks of 

 granite and gneiss, some as large as a Swiss cottage, which rest on 

 the limestone rocks of the Jura. Now the nearest granite and 

 gneiss rocks are those of the Alps, from which it is certain those 

 blocks have been derived, although the great and deep valley 

 of Switzerland, upwards of 50 miles broad, separates the two 

 ranges. 



* While Captain Newbold was writing this forcible passage at Kurnool, Lieute- 

 nant Sherwill was forwarding to the Society from Behar the splendid map and col- 

 lection of specimens which we noted in our Proceedings of January 1845, and 

 which the Society has most properly brought to the special notice of Government. It 

 is impossible to give a better illustration of the truth of these remarks.— Eds. 



