446 T. Mellard Reach — Keuper Marls at Great Crosby. 



where shown to be a glacial marine deposit.^ It is full of the usual 

 erratics, Silurian grits, grey granites, and greywackes from the Soulh 

 of Scotland, English Lake rocks, and Carboniferous Limestone and 

 sandstones from the Pennine chain. The most peculiar feature in 

 this instance is the large blocks of Lower Keuper sandstone, which 

 rest on, and in some cases appear to be actually compressed or forced 

 into, the marls below. This is the first instance of the kind I have 

 met with in the neighbourhood of Liverpool, where the erratics at 

 the base, if they are not on the rock, rest tranquilly on or partially 

 in the red sand which often covers the Triassic sandstone. 



The Boulder-clay for the purposes of brick-making is washed in 

 a large cylinder containing revolving arms, the " slip " being run 

 into settling-pits, the stones remaining behind. Much of the sand 

 which is intimately mixed with the aXsiy separates in these pits and 

 is deposited near the mouths of the wood-shoots conveying the 

 muddy liquid to the pits. Numerous fragments of marine shells 

 can be seen in this washed sand which embedded in the clay are 

 indistinguishable. 



The shales below are, however, the feature of most interest in the 

 locality. At first sight they look uncommonly like some of the Coal- 

 measure shales ; indeed so much so that one of the workmen fx'om 

 Staffordshire told me he thought coal would be found underneath. 

 There can, however, be little doubt that they belong to the Keuper 

 marls, and probably the lower portion of them. Their thickness has 

 not been tested. They appear to have a general dip south-west, 

 and in one place it was as much as 20°. The shales are however 

 much disturbed, and at the west side of the pit two anticlinals were 

 to be seen, but they are obscured at present from the slipping of the 

 Boulder-clay from above over them. There are several bands of 

 harder shale interbedded in the marls, one being 10 inches thick, of 

 a very fissile character. At the north end of the excavation is a band 

 of sandstone of a very friable nature, composed of loosely agglutinated 

 rounded quartz grains resembling in appearance some of the sandstone 

 in the quarry at Little Crosby. I observed some very large ripple- 

 marks on the surface of this band, but there are no pseudomorphs 

 of crystals of chloride of sodium anywhere that I could discover in 

 the shales. One of the hard bands appeared to be an impure lime- 

 stone, and effrevesced strongly with acid, but the shale generally 

 appears quite free from lime. The general colour of the whole 

 deposit is a bluish grey. The method of treatment for brick-making 

 is this : the argillaceous shales, excluding the hard bands and sand- 

 stones, are mixed with a little of the " slip " from the Boulder-clay, 

 then ground in a mill, and forced in a plastic mass through a die and 

 cut into bricks by wires fixed in a movable frame. The bricks it will 

 be seen are free from the pebbles and limestone always contained 

 in the local Boulder-clay bricks. 



The extent of this deposit of Keuper marls is quite unknown. 

 At all other exposures in Great and Little Crosby the rock is Lower 

 Keuper sandstone. Nearly the whole district is covered with a 

 1 Drift Beds of the North-west of England, Q.J.G.S., May, 1883. 



