﻿Rev. T. G. Bonney — The LherzoUte 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 number of scattered boulders, and the peculiar weathering of 

 the limestone, which forms deep fissures (like the karrenfeJder of the 

 Alps), harbouring a rich 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, and 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 blocks made 

 it difficult to examine this in situ, but it appeared to be about three 

 or four yards wide, and to cut across the Lherzolite roughly 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 

 blocks 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 extremely 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 slight 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 



