PETEOGRAPHIC GEOLOGY AND DESCRIPTIONS. 219 



Basalt. Diabase . ] 



No. 142A. BASALT. ( 'Amygdaloidal. ) 



Evidently from one of the amygdaloidal layers mentioned under No. 142. But there is no mention of this 

 number (142A) in the field notes in the Ninth Annual Report, page 36. 



Meg. A very fine-grained, reddish-brown rock, filled with laumontite amygdules. 



Mic. Small, lath-shaped plagioclases, more or less reddened, a little augite, mag- 

 netite and hematite constitute the slide (except the laumontite). The rock has been 

 much altered. The laiuiumtite, which fills the amygdules, has penetrated the whole 

 rock and has replaced a large part of it. 



Age. Cabotian. 



Remark. This rock is similar in structure and occurrence to Nos. 95, 97, 99 and 

 101, at Agate, bay. u. s. G. 



No. 143. DIABASE. 



The rock" which forms the fourth fall of Baptism river. The fall embraces the whole river in one narrow 

 cleft and descends nearly perpendicularly. It is more crystalline than the others, and is very much more so 

 than is No. 142. It resembles the great diabase Nos. 112, 141, etc . 



Ref. Annual Report, ix, pages 36, 37. 



Meg. A rather coarse-grained diabase, showing lustre mottling. 

 Mic. A usual section of coarse diabase, consisting of plagioclase, augite, mag- 

 netite and alteration products. Rock somewhat altered. 

 One section. 



Age. Cabotian. u. s. G. 



No. 144. DIABASE (at contact). 



Baptism river. "The river bed is then filled with large boulders of No. 143 for some distance, and all dip 

 and strike are lost. The next that appears is a closely-jointed dark rock, some times having red belts, and calcite 

 seams, but mainly black. In this kind of rock is an abandoned exploration for copper, some distance above 

 [below] the fourth fall. There are also in the river bed along this place, large detached masses of feldspar rock." 



Ref. Annual Report, ix, page 37. 



Meg. A dark -gray, compact, very fine-grained rock whose constituents cannot 

 be distinguished, but which has the appearance of a very fine-grained diabase. Along 

 seams the rock becomes brown. Another specimen, also marked No. 144, is a very 

 fine-grained, red-brown, siliceous rock, looking like a vein rock, which contains some 

 calcite. This probably represents the " red belts " spoken of above and is not repre- 

 sented by any section. 



Mic. The section is composed of jt/nf/inclane, jujruxene and magnetite. The pla- 

 gioclase is in microliths and in more or less allotriomorphic individuals which are 

 frequently larger and of later date than the microliths. With this allotriomorphic 

 feldspar is pyroxene in small, irregular grains, much charged with magnetite. The 

 latter mineral is very abundant in the section. In general structure and composi- 

 tion this rock is very similar to No. 131, except that No. 144 is much finer grained 

 than No. 131, and the pyroxenes are not so distinctly rounded as in No. 131. 



One section. 



Age. Cabotian. u. s. G. 



