394 ON THE TRIASSIC ROCKS OF SOMERSET AND DEVON. 



country (where the old rocks were chiefly composed of Carboniferous 

 Limestone), the prevalence of arenaceous deposits at the base of the 

 Trias fringing the north-east and south slopes of the Devonian grits 

 and shales of the Quantocks, the basement breccias and sands of the 

 West Somerset and South Devon Trias (where the older rocks chiefly 

 consist of Culmiferous and Devonian shales and grits), and the ad- 

 mixture of calcareous material in the form of derived fragments or 

 in the matrix in places where neighbouring exposures of limestone 

 were favourable for their production; so that we are not only 

 unable to see any reason why the Muschelkalk should present similar 

 characteristics in different areas, but fail to see why its repre- 

 sentative should form a perfectly distinct division. 

 . Whether the Budleigh pebbles travelled from Normandy or Corn- 

 wall, their advent seems to mark an epoch in the Triassic history of 

 Devon, when either by the breaking of a barrier, allowing the in- 

 cursion of foreign sediments into a salt lake or inland sea, or by a 

 natural extension of the local sources of derivation, a supply of 

 foreign material was swept into the area, furnishing the depositing 

 agents with a different supply from that which had before been and 

 was afterwards afforded by the local rocks. 



In the Geological-Survey memoir on this area the bibliography of 

 the subject will be gone into, and these few precursory notes will be 

 modified and strengthened, when additional observations, greater 

 latitude, and time allow us to enter into details and amplify many in 

 our possession not alluded to here *. 



Discussion. 



Mr. Etheridge remarked that the Rhaetics form a most im- 

 portant feature in Somersetshire. He thought that the ignorance 

 of the Triassic rocks so common among geologists was to be ascribed 

 to a great extent to the want of interest attaching to these non- 

 fossilif erous red beds ; and hence our thanks were due to those who, 

 like Mr. Ussher, would work upon them. 



Prof. Ramsay said that Sir Henry De la Beche grouped the whole 

 of the Triassic rocks together, but nevertheless there was no doubt 

 that he fully understood their nature. In passing over part of the 

 country, he had once fancied that some of the lower breccias might 

 be Permian ; but he had never been able to investigate the matter. 



The Author remarked that if the Lower Breccias were Permian, 

 the Bunter and Muschelkalk must be also represented, in the absence 

 of unconformity. 



* Should any of my observations tally with those of my predecessors in the 

 field, I have only to state that the latter part of this epitome has in a still more 

 abstracted form appeared in the ' Geological Magazine,' dec. 2, vol. ii. No. 4, 

 April 1875, and has been strung together and condensed entirely from my own 

 notes and observations. 



