3 2 FRA NK DA WSON A DA MS 



but the appearances in the field rather favor Lacroix's interpre- 

 tation. 



The next day the party, leaving Ax-les-thermes, drove to 

 Foix, visiting on the way the gypsum quarries near Tarascon. 

 The gypsum is of Triassic age and is seen to have resulted from 

 the alteration of anhydrite. It contains intercalated marly beds 

 holding dipyre, tourmaline and other minerals, which are believed 

 to have been developed in them by an intrusion of ophite, which 

 however is not exposed in the immediate vicinity. 



On August 8th a visit was paid to a great mass of " Cipolin," 

 intercalated in the gneiss near Arignac, which is locally rich in 

 various minerals of the humite group and containing also spinel, 

 plogopite, rutile, etc. The name "Cipolin" is given by the 

 French geologists to any crystalline limestone intercalated in 

 gneiss, even although it be free from the micaceous minerals 

 which give to the typical "Cipollino" its distinctive character. 

 This mass is from 200 to 300 meters wide and is identical in 

 character with the limestone found in many parts of the Lauren- 

 tian in North America. The enclosing gneiss is said by Lacroix 

 to contain garnet, and also to differ somewhat in other respects 

 from the granite of the vicinity of Ax-les-thermes. Its origin is 

 unknown. 



In the afternoon other large exposures of crystalline rocks 

 near Cabre were visited. These consisted of epidosite, quarried 

 for road metal, containing large lumps of malacolite in places 

 and traversed by little graphite seams. This epidosite is believed 

 to be an altered limestone, and is interstratified with bands of a 

 peculiar dark fine-grained micaceous gneiss, exactly like that 

 which is so uniformly associated with the limestones of the 

 Laurentian in Canada and in the Adirondacks. The age of these 

 crystalline rocks has not as yet been determined. 



In the evening the party reached Vicdessos, some seventeen 

 miles west of Ax-les-thermes, a most picturesquely situated 

 little mountain village, from which excursions were made on the 

 two following days. Our route on the first of these days led up 

 to the quaint little village of Sem, where the renowned iron 



