rence of crystallization, producing several generations of crystals, but 

 it is a structure exhibiting contrasts in the size and form of the com- 

 ponent crystals of a rock, resulting from the differences in conditions 

 under which the different minerals crystallized. 



Granophyre of Carrock Fell, England. — In the tarrock Fell 

 district is a red granophyre closely associated with the gabbros. This 

 rock has recently been studied by Harker, 5 who had previously inves- 

 tigated the gabbros. The normal type of the granophyre is an augitic 

 variety in which the augite occurs as a deep green species which is idio- 

 morphic toward the feldspars. Oligoclase is also present as idiomorphie 

 crystals in a reddish quartz-feldspar groundmass with the typical gran- 

 ophyric structure. The composition of the rocks is represented as fol- 



8iO, 



As the rock approaches the gabbro it becomes less acid and the pro- 

 portion of augite in it increases. This is the lower portion of the mass 

 as it was originally intruded. Its more basic nature as compared with 

 the rest of the rock is explained as due to the absorption of parts of the 

 gabbro with which the granophyre is in contact. 



The same author 6 also records the existence of a greisen, which is a 

 phase of the well known Skiddau granite. The greisen consists essen- 

 tially of quartz and muscovite, but remnants of orthoclose are still to 

 be detected in it. The mica is regarded as having been derived largely 

 from the feldspar. 



Sheet and Neck Basalts in the Lausitz.— The basalts of the 

 neighborhood of Seifeirnersdorf aud Warnsdorf in the Lausitz, Saxony, 

 occurs in sheets according to Hazard, 7 and in volcanic rocks. The 

 sheet rocks are nepheline basalts, nepheline basanites aud feldspataic 

 glass basalts. The neck forms are hornblende basalts, sometimes with 

 and sometimes without nepheline. The constituents of all are magne- 

 tite, apatite, augite, biotite, nepheline and glass in varying quantities, 

 with feldspar, olivine and hornblende in different phases. Sometimes 

 the mineral nepheline is absent, but this happens mainly in the glaesy 

 varieties, where its components are to be found iu the glassy base. 

 There are intermediate varieties between the hornblende and the oli- 



s Quart. Journ. Geol. Soe., 1895, P . 125. 



