494 Dr. W. T. Blanford — Striated Boulder from Salt Range. 



to grinding processes from different directions, but its exactly opposite 

 side was even more perfectly smoothed and marked than any other ? 



2. On the supposition that ice was an agent in the case, does the 

 difference in the angles of the faces and the direction of the striation 

 afford a measure of the plasticity of ice ? 



3. What form of ice agency may have been the originating cause, 

 shore, ground, floe, floating or glacier ice ? 



4. Was the pebble continuously frozen in or free at times, and was it 

 imbedded in a moving ice mass, or held so as to oppose such a force ? 



5. Could any other agency than that of ice have produced the 

 result ? 



These questions were laid before the Section, in order to obtain 

 general and valuable opinions, or elicit suggestions upon a point of 

 great interest, in any case, but particularly, as bearing upon the 

 existence of an earlier glacial period than that so well known to 

 modern geologists ; and one which has left its trace in regions where 

 glaciers cannot now possibly exist, though these are found, at a 

 distance, in the higher regions of the Himalayan chain ; but even 

 there entirely dissociated from direct connexion with any portion of 

 the Salt Eange Geological Series. 



IY. — Notes on a Smoothed and Striated Botjider erom a Pre- 



TERTIART DEPOSIT IN THE PUNJAB SALT RANGE. 1 

 By Dr. W. T. Blanpord, F.E.S., Sec. Geol. Soc. 



THE block of stone in question, like another exhibited by Mr. A. B. 

 Wynne, was obtained by Dr. Warth, at Chel Hill, in the Punjab 

 Salt Range. This specimen was sent by Dr. Warth to Mr. H. B. 

 Mecllicott, Director of the Geological Survey of India, who forwarded 

 it to the present writer, in the hope of learning the views of those who 

 have most experience of similarly marked boulders, and of ascertaining 

 whether the peculiar characters of the present specimen are due to any 

 particular form of ice action or to any other agency. 



The stone consists of a purplish-brown porphyry, apparently an 

 altered felspar-porphyry. This rock is known to occur in Rajputana, 

 near Jodhpur, between 300 and 400 miles south of the Salt Range, 

 and belongs to a group of beds supposed to be Archaean, and known by 

 the name of Malani. These rocks may occur nearer to the Salt Eange, 

 but the intervening country is imperfectly known, and is much covered 

 with river alluvium and blown sand. 



The boulder exhibited measures 1\" x 6" X 3J". It is subangular, 

 the two principal surfaces are plane, smooth, finely striated, opposite 

 to each other, and nearly but not quite parallel. Each of these sur- 

 faces is bevelled off on one edge by a number of smaller facets, meet- 

 ing the principal surface and each other at very obtuse angles. Besides 

 the larger plane surface there are on one side five smaller smoothed 

 facets, and on the other two, but one in each case is ill-marked, the 

 angle at which it meets the next surface being so obtuse as to be with 

 difficulty recognized. All the smoothed surfaces on one side are 

 striated in the same direction; those on the other side are striated 

 1 A paper read before the British. Association, Birmingham. 



