90 



Mr. H. Strickland the suggestion, that tliey were cauised by currents 

 of water, or by the action of wind during ebb-tide. ' ■■ 



; Among the terrestrial phsenoniena which have recently excited 

 notice, is the discovery by Dr. Riley of a bone-cavern in the Moun- 

 tain Limestone of Durdham Down near Bristol, the opening of which 

 has been conducted by Mr. Stutchbury, who has described its con- 

 tents. Distingui;shing, as Dr.Buckland had formerly done, the cavities 

 formed by fissures in the rock, into which bones had been washed 

 with detritus of rocks and soil, or into which whole animals had 

 fallen, from caverns inhabited by extinct species of canine animals, 

 Mr. Stutchbury shows, that the facts observed in this case entirely 

 iavour the latter hypothesis, the bones (among which those of the 

 hyeena vastly preponderate) being fractured into small bits without 

 the admixture of any rolled or far-transported detritus. The most 

 novel point connected with this cavern is, that several of the hard- 

 est bones and teeth have been split across, and their parts relatively 

 moved, as if the detrital mass had been affected by faults posterior 

 to its original deposit, which movements may, Mr. Stutchbury sup- 

 poses, have been connected with the operations which closed the ori- 

 fice of the aperture *. 



Geological Dynamics. — Detrital Phixnomena. — Raised Beaches 

 and Shingle Terraces.— Marks of Ancient Levels of tJie Sea. — ^^In 

 previous yeai's Mr. Hopkins led the way in applying mathematical 

 and mechanical knowledge to geology, and in a memoir which will, 

 I trust, soon appear in our Transactions, he shewed satisfactorily, 

 that the transverse fissures through the ranges which bound ellipti- 

 cal areas, are the necessary mechanical efi'ects of the upheaval of 

 such districts. He now lays before us a memoir on the elevation 

 and denudation of the lake districts of Cumberland and Westmore- 

 land, in which, going furthei', he encounters some of the most difK- 

 cult problems in geological dynamics. The first of these is to re- 

 construct exactly the former conditions of this district, and certain 

 data being assumed, to deduce a series of geological events, the oc- 

 currence of which would explain the present position of the dif- 

 ferent rocks, as so many fragments of a former whole, which has 

 been broken up at two distinct periods of eruptive agency. If all 

 the premises which Mr. Hopkins assumes be granted, there can be 

 little doubt, that with his profound mathematical and physical know- 

 ledge, his deductions will be accurate ; but I confess that two of his 

 postulates, viz. a perfectly smoothed down surface of the older rocks 

 anterior to the deposition of the Mountain Limestone, and the former 

 persistence of a continuous mantle of the latter rock over the transi- 

 tion, metaraorphic and plutonic rocks, seem to me to be very difficult 

 to understand. 



On I'eferring to the opinions which Professor Sedgwick has pub- 

 lished on the structure of the Lake Country-]-, I perceive, that 



* A similar case occurred in the gravel beds of Darmstadt, where thft 

 Dinotherium was found. 

 f Letters to Wordsworth in the New Guide to the Lakes, 



