EXCURSION TO THE PYRENEES 37 



hornstone and the more siliceous bands. A few granite dikes 

 and a mass of granite, apparently of comparatively small dimen- 

 sions, occur on one side of the Cirque, while the other side is 

 free from granitic intrusions. In these dikes, and also in the 

 hornstone near the contact, axinite occurs in masses of consider- 

 able size. In the dikes this mineral occurs as rather coarsely 

 crystalline streaks, in some cases on the walls and in others 

 within the dike itself. In the hornstones it occurs as an impreg- 

 nation, apparently partially replacing the other constituents of 

 the rock. The petrographical character of the various rocks can 

 be well seen in the immense talus piles at the foot of the cliffs, 

 which also afford an excellent opportunity for collecting. From 

 a petrographical standpoint this was one of the most interesting 

 localities visited on the excursion. 



The excursion, as originally planned, was to have terminated 

 here, the party returning to Bagnieres-de-Bigorre and then 

 taking the train to Paris ; but the majority of the party willingly 

 accepted the proposal made by Professor Lacroix to extend the 

 excursion by another day and visit Bareges. Accordingly, they 

 left Payole on the morning of August 14th, and drove to Gripp, 

 and thence walked to the Col du Tourmalet, over a great series 

 of highly inclined and more or less altered clay slates, lime- 

 stones, etc., of Upper Silurian and Devonian age. Magnificent 

 views of the Pic du Midi, the highest point of the French 

 Pyrenees, were obtained at a number of points along the route. 

 The ascent was long, the day very hot, and shade by no means 

 so abundant as could have been wished, but the Col du Tour- 

 malet was at length reached, and the very abrupt descent made 

 into the valley of the Bastan, over magnificent rock exposures. 

 The granite appears near the head of this valley, and at its 

 contact with the stratified series there appears a mass of rock 

 consisting of a mixture of actinolite and axinite. The contact 

 was not seen by the writer, but Professor Wolff, who saw it, 

 states that the margin of the granite seemed to be well defined, 

 although somewhat melted into the actinolite axinite rock above 

 mentioned. As the evening was closing in, however, there was 



