HuTTON. — Geology of the Trelissick Basin, 399 



glacier epoch in a lake formed by the Waimakariri glacier 

 blockiBg up the valley. The occurrence of pebbles of liparite 

 in the conglomerate is very interesting. Similar pebbles have 

 been noticed by Dr. von Haast in the Big Ben Coalfield on the 

 northern side of the Thirteen-mile Bush Eange,* which is about 

 half-way between the liparites at Malvern Hills and Craigie- 

 burn ; and as no rocks of the same kind are known to the west 

 or north of Craigieburn, it seems necessary to suppose that 

 these pebbles of liparite were brought fi-om the Malvern Hills 

 by a river running to the north. Now the High Peak Eange, 

 in the Malvern Hills, attains an altitude of 3,000 feet ; the 

 conglomerates at Big Ben are 2,800 feet above the sea ; Lake 

 Lyndon is 2,743 feet ; Craigieburn Saddle, 2,619 ; and Lake 

 Pearson 2,085 feet. So that there is, even now, sufficient fall 

 in this direction for a river ; and I shall show in the sequel that 

 this gradient was probably steeper in the Waipara period. We 

 are, however, met with the difficulty that the Big Ben conglo- 

 merates are, according to Dr. von Haast, surrounded by hills 

 4,000 to 5,000 feet high, the drainage now being from there 

 mto the Kowhai, Probably this ancient river passed over the 

 southern flank of the Thii'teen-mile Bush Eange ; but we must 

 wait for more information before a complete solution of the 

 problem can be attempted. 



Fossils. — In the beds above the coal at Cragieburn I found 

 fragments of leaves of angiospermous dicotyledons, and ferns 

 have also been obtained from here. Both ferns and dicotyle- 

 dons have been found in Murderer's Creek, about a quarter of a 

 mile above Parapet Eock, in connection with a thin seam of 

 coal.f The greensands at the lower part of the Broken Eiver 

 contain quantities of a large undescribed species of oyster, 

 apparently identical with one found near the coal at Malvern 

 Hills. Below these oyster-beds Mr. McKay collected, in 1877, 

 ConchotJiyra parasitica, together with undescribed species of 

 Perna and Corithium : and on the south side of Prebble Hill a 

 Tellina. From this last locality, Mr. Enys has a tooth of 

 Myliobatis, different from those found in the Pareora rocks. 

 The marls contain Ostrea subdentata, Hutton,| on the left bank 

 of the Porter, near its junction with the Broken Eiver ; also 

 just above the first limestone gorge of the Porter Eiver. Ac- 

 cording to Mr. McKay this species was collected by Dr. Hector 

 in the greensands, but Mr. Enys knows it only from the marl. 

 The so-called " fucoid markings" are also common in the marl 

 at the first limestone gorge, as well as scales of Teleost fish. 



* " Eep. Geo. Expl.." 1871-72, p. 21. 



t Potamogeton ovatus, figured in the " Catalogue of Geological Exhibits, 

 Indian and Colonial Exhibition," p. 61, probably came from here. 



I Perhaps the same as 0. alabamamensis. Lea, from the Eocene of 

 Alabama. 



