3-i2 Ernest W. Sheats : 



Dinesus material is also similar, and the cherts of Lady's Pass 

 appear to differ from it only in a more complete silicification. 



6. — Relations of the Dinesus Beds to the Ordovician and to 

 THE Diabase. 



On Quarter Sheet 80 these beds are shown in the Parish of 

 Knowsle}' East as a narrow band up to a quarter of a mile in 

 breadth, stretching northwards from the northern end of allot- 

 ment 3 to the middle of 3k. Their eastern boundary is the 

 diabase series, and the bedded silicified fragmental diabase re- 

 corded as " Metamorphic." Their western boundary is with 

 the Ordovician shaJes, and the boundary taken by Mr. Ferguson 

 was a thin bed of a " brecciated-conglomerate.'' Alono; the road 

 running west from the Murray road, and separating allotments 

 3m and -3], a small section is to be seen in which the strike of 

 the rocks is almost N. and S., and the dip abovit 70 deg. to the 

 W. The section shows from E. to W. a few feet of the upper 

 beds of the Dinesus series, consisting of brown shales and mud- 

 stones partially silicified. These are suoceeded by the brecciated- 

 oonglomerate about 2 inches in thickness, consisting of sub- 

 angular fragments of shaly material, and cherty fragments set 

 in a fine groundmass. Succeeding these are mudstones with 

 smaller fragments forming, according to Mr. Ferguson, the 

 lowest beds of the normal Ordovician series here. A specimen 

 taken about 20 feet W. of the brecciated-conglomerate consists of 

 a bedded, rather dense, light-coloured, somewhat cherty rock con- 

 taining little black spieoks, which were at first thought to be 

 small fragments of an older black chertr. Under the microscope. 

 however (Sec. 634) (PI. XVI., Fig. 4), these siiow as quite colourless 

 areas, with no defined boundary, but passing gradually into the 

 groundmass of the rock. There can be no doubt that the}' are 

 secondary in origin, and reiDresent local segregations of chalce- 

 donic silica in a less siliceous matrix. 



The brecciated-conglomerate also contains fragments of what 

 in the hand specimen lonk like a black chert. UndcM' the 

 microscope (Sec. 618) (PI. XI\^., Fig. 1), it is seen to consist of frag- 

 ments of altered diabase, and of a fine-grained mck, possibly 

 diabase tuft'. All of the fragments are more or less silicified, 



