Itev. T. G. Bonney — The Lherzolilc of the Ariege. 61 
Time did not allow me to cross the valley and examine the 
junction with the limestone on the opposite side, where it was well 
exposed for a considerable distance at the base of a sort of cliff ; but 
as far as I could see it was rather wavy and uneven, as if the Lherzo- 
lite were intrusive. I followed the junction on the east side of the 
pool for a considerable distance. Unfortunately the abundant herbage, 
the n umber of scattered boulders, and the peculiar weathering of 
the limestone, which forras deep fissures (like the karrenfelder of the 
Alps), harbouring a rieh Vegetation, prevented me from obtaining a 
single actual contact : but as the Lherzolite clearly appears here and 
there to protrude in broad tongues into the limestone, and this is 
highly crystalline (being quite white and saccharoidal) near the 
junction, I have little doubt the rock is intrusive. That it is an 
igneous rock I think no one who has examined it will dispute. 
There are, however, I think, no proofs of eruption, though a breccia 
of angular fragments of Lherzolite and limestone might seem at first 
sight to be a volcanic agglomerate, aud so even favour the idea of 
contemporaneous volcanic action. According to Prof. Zirkel this 
breccia occurs here (and here only) between the Lherzolite and the 
limestone. I did not, however, observe it at this part of the junc- 
tion, but found a dyke-like mass of brecciated Lherzolite on the 
opposite side of the Etang. The numerous fallen biocks made 
it diflöcult to examine this in situ, but it appeared to be about tliree 
or four yai'ds wide, and to cut across the Lherzolite rougbly from 
E. to W. As far as I observed, however, this rock was com- 
posed only of Lherzolite, and I fully believe it only to be a 
friction breccia, and not at all of the nature of a volcanic agglome- 
rate. The other masses of breccia which I examined were on the 
grassy hill-side nearer to the Col d’ Erce, not far from where 
there is another small patch of Lherzolite on Prof. Zirkel’s 
sketch-map. These, however, appeared to me to be in every case 
erratics, and I could not see the rock in situ, on the hill above. 
My time, however* was too limited to allow of a long search. These 
biocks varied from a breccia of angular and subangular fragments of 
Lherzolite, frequently more than three inches in diameter, imbedded 
in a ferruginous paste which often appears to consist mainly of 
minute fragments of Lherzolite, to an extrem ely pretty rock chiefly 
composed of fragments of white marble, often from a half to one 
inch diameter, imbedded in a speckly yellowish or greenish grey 
matrix, with a sliglit ruddy tinge. In the time at my disposal I 
collected four varieties of the breccia, forming a fairly complete 
series. The first is exclusively made up of Lherzolite, and so 
thoroughly compacted that (as in many ancient breccias) it is 
often not easy to distinguish the fragments, except on a weathered 
surface. The second consists mainly of Lherzolite fragments with 
a very few small pieces of marble, but here and there there is an 
appreciable proportion of minute calcareous fragments in the matrix. 
In the third, the marble predominates, but the paste contains a large 
quantity of comminuted Lherzolite; and in the fourth fragments of 
marble abound, but those of Lherzolite are rare, though this rock 
