42 



of different localities naturally displayed, and in a manner most 

 unmistakable. 



The flat-topped hills and tablelands, which without seeming 

 method or system occur throughout the whole of the Cretaceous 

 basin now under discussion, are but remnants of the one vast 

 deposit, now in part removed, but of the nature of which their 

 faces are the typical sections. 



The lowest stratum disclosed is a bed of blue clay, greenish 

 when weathered, and more or less sandy in its upper portion. It 

 lies horizontally, or nearly so ; the clay is brittle and very reten- 

 tive of water, and at considerable depths in it are thin seams of 

 limestone made up of shells and casts, which are so brittle that 

 an attempt to extract any probably results in destroying the 

 specimen. Spheroidal masses of argillaceous limestone up to twO' 

 feet in diameter are frequent; they do not contain any fossil 

 remains, and are usually coated with a thin layer of gypsum. In 

 fracture they break into pei'fect segments, proving the homogene- 

 ity of their structure, and tliat tlie form is not due to abrasion. 

 The colour is "dark stone," but in thin edges of a translucent 

 "honey colour." Gypsum is al)undant in thin plates ; it is to be- 

 remarked that I seldom met with it among the fossils, or rather 

 the fossils seem to be situated down in the clay beds heJo2c that 

 portion in which the gypsum is developed. 



Above the blue clay is a stratum of argillaceous ironstone in 

 form of nodules, concretions and thin sheets. It varies in thick- 

 ness from a few inches up to ten or twelve feet, and seems to haA'e 

 been formed in flne sand, for most of the nodules are simply 

 cases filled with white sand. On exposed places these nodules by 

 weathering permit the escape of the sand, and then the aspect of 

 the deposit is that of scoria from a huge smelting furnace. Near 

 the Peake Range, this belt of ironstone is charged with fragments 

 of semi-opal and quartz, and might fairly be termed a conglomer- 

 ate rock. The quartz is evidently derived from the veins among 

 the schists, forming the mass of the ranges, and is coarser the- 

 nearer the ranges are approached. 



Above the ironstone band is a stratum upwards of 200 feet 

 thick of a friable white sandstone composed of clear white grains 

 of sand cemented together with an argillaceous paste. At time* 

 the jDaste is in excess, and then the faces of the hills and blufls. 

 have a white chalky appearance, and sometimes, though rarely,, 

 contain gypsum in the portions near the ironstone band. To- 

 wards the top the grit becomes more compacted by infiltrated 

 silica, and tlie top is composed essentially of a capping of porcel- 

 ainised sandstone from one to six feet in thickness ; in fracture 

 it is evidently a sandstone, and the weathered surface has always 

 a glazed aj^pearance and superficial staining by oxide of iron.. 



