16 



THE GEOLOGIST. 



character ; were it not that every gradation can be readily supplied, it 

 would be sometimes, at least, a little puzzling to recognize a member 

 of the Dartmoor family of rocks in the fragments met with along the 

 river-courses, and which have yielded to the various influences to 

 which they have been exposed since leaving home. It is these 

 travelled masses which must tell us whether the red conglomerates 

 of Devonshire contain specimens derived from th« central upland of 

 the county; and I have no hesitation in believing that every one ap- 

 proaching the subject in this way would pronounce the North Taw ton 

 pebbles to be of Dartmoor origin. 



In August last (1861), I met Mr. "William Vicary, — who now 

 resides at Exeter, and is devoting himself, with great diligence and 

 success, to the geology of that neighbourhood, — and again introduced 

 the subject of the North Tawton pebbles ; on which he informed me 

 that he had recently found unmistakable Dartmoor fragments in the 

 red conglomerate of Great Haldon, a well-known hill about five miles 

 south of Exeter ; and that a friend, to whom he had mentioned his 

 discovery, had called his attention to the following passage in Brice's 

 ' History of Exeter.' The author is describing the Haldon red con- 

 glomerate, and says, " In it we have often found rounded pebbles, and 

 pieces of granite of the same form"* 



A fact of so much interest was not to be neglected ; accordingly we 

 took an early opportunity of starting for Haldon. Passing through 

 Alphington and Kennford, and leaving the great road from Exeter 

 to Plymouth by Chudleigh and Ashburton, on the right, for that 

 which passes over Haldon, in a more easterly direction, to Newton- 

 Bushel, we reached our ground, about five miles and a half from Exeter; 

 and Mr. Vicary at once pointed out one or two well-marked frag- 

 ments of the true Dartmoor series of rocks in the conglomerate, but 

 so far decomposed and disintegrated that it was impossible to extract 

 them in their integrity ; a further search was soon rewarded with 

 several less perishable specimens, amongst them representatives of 

 each kind of granite recognized by Mr. Austen in the Dartmoor 

 country; namely schorlaceous granite, porphyri tic granite, and elvan. 



On our way back to Exeter, we detected two or three well-marked 

 specimens near Peamore, about two miles and a half from the city. 



That part of Haldon at which the pebbles are met with is about 

 five miles, in a straight line, from the nearest point of the granite ; 

 the fragments found at Peamore must have travelled something more 

 than a mile further. The red conglomerate approaches to within 

 about the same distance from the granite at Newton-Bushel, and 

 several other places ; the fact, if it be one, that no such pebbles have 

 been found in these localities, should stimulate to further and careful 

 search ; and if, after all, they really do not exist there, it need not be 

 a matter of very great surprise; changes in the physical geography 

 of the district, amply sufficient to account for it, may have occurred 

 since the period of the red conglomerate. 



I may state here that during the spring of the present year (1861), 

 * 'History of Exeter,' by Thomas Brice, 1S02, p. 114.. 



