.46 E. 0. Teale: 



No. 40. — Diabase on spur, east of Blackbird Creek, north of 

 Howqua River, and about one mile E.N.E. of Fry's. A rock type 

 in whicli augite and its alteration jDroduct chlorite predominate 

 and felspar i'S in subordinate amount. Some of the felspar prob- 

 . ably preceded the augite in crystallizing, and recrystallization of 

 felspar, with resulting inclusion of chlorite has probably oc- 

 curred. Ilmenite granules have changed to sphene. 



No. 41. — Diabase from Castle Rock, Lick Hole Creek. A 

 diabase whicli has suffered much secondary albitization. Augite is 

 altered to pale and to brown secondary hornblende. The original 

 felspar is noAv quite cloudy, chlorite is developed, and an irregular 

 vein of secondary albite or albite-oligoclase traverses the section. 

 It looks like quartz in ordinary light, but isi identifiedi by the pre- 

 sence of some lamellar twinning, by its refractive index, which is 

 less than 1-53 and by biaxial figures with positive signs. Ilmenite, 

 more or less altered to sphene, and hematite, are present. The 

 albite in the vein occurs in clear interlocking crystals, associated 

 with calcite, and with fibrous secondary hornblende. 



No. 42. — Diabase, near No. 41. A rock similar to No. 41, but 

 with only a minute vein of secondary albite, traversing the 

 section. 



No. 72. — Silicified fine-grained diabase from Four Mile Creek, 

 near the massive black bedded cherts at the north-east margin of 

 the main diabase mass. In the fine-grained diabase area a little 

 augite remains, but most of it is altered to chlorite and secondary 

 hornblende. Lath-shaped, water clear felspars, with chlorite in- 

 clusions occur. Sporadic secondary quartz occurs in granules in 

 the mass of the diabase, but in over half the section the diabase 

 has been completely replaced by a radial and granular aggregate of 

 chalcedonic silica, with some coarser grained quartz crystals. The 

 rock has a spotted appearance, due tn greater concentration of 

 felspar laths in roughly circular areas. 



No. 73. — Diabase from Four Mile Creek, near to 72. This rock 

 is rather coarse grained. Brown unaltered augite and large lath- 

 shaped albite or albite-oligoclase, many with chlorite inclusions, 

 form the; bulk of the rock. Opaque iron oxide is fairly abundant, 

 and large areas of chlorite, apparently not derived from augite, 

 occur. 



No. 107. — Diabase from spurs south of Barney Creek, at south- 

 east end of main diabase mass. The rock may be described in its 

 -present condition as a micrographic quartz-diabase. Some original 



