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 the 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 Tawtou 
pebbles to be of Dartmoor origin. 
In August last (1861), I met Mr. William Yicary, — 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 JN^orth 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 Keunford, 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 miles and a half from Exeter; 
and Mr. Yicary 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, porphyritic granite, and elvan. 
On our way back to Exeter, we detected two or three well-marlted 
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 miust 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 sufiicient to account for it, may have occurred 
since the period of the red conglomerate. 
1 may state here that during the spring of the present year (1861), 
* 'History of Exeter,' by Thomas Brice, 1802, p. 114. 
