120 GEOLOGY MAITLAND-BKANXTON DISTRICT, 



Edmondia{1) nobilissinia. Conularia laevigata. 



Deltopecten subquinqnelineatus. Plant-stems. 

 M<foiiia, 3 spp. 



One hundred and fifty feet below the top of these mudstones, 

 (or 2,450 feet above the base of the marine beds), in a band of 

 dark-coloured, sandy, calcareous mudstone, numerous specimens 

 of the pseudomorph Glendonite were obtained. Further details 

 of this are embodied in a separate note. 



Following the mudstones, there is a development of a coarse 

 conglomerate with large waterworn pebbles, chiefly composed of 

 andesite, followed by a rather soft gritty sandstone, and then a 

 rather coarse, greenish, tuffaceous sandstone. These together form 

 a thickness of strata of about 250 feet. The conglomerate is known 

 as the Allandale Con glomerate,, and contains an abundance of large 

 molluscs with thick shells, such as Euri/desma eordata, Platy- 

 scliisma oculus, Keeneia platyschismoides, etc. The greenish, tuffa- 

 ceous sandstone is the Harper's Hill Sandstone. These beds are 

 only developed locally in the neighbourhood of Allandale. Towards 

 the south-east, they seem to give place to a development of tuffs 

 associated with the hypersthene-andesite of Blair Duguid Hill. 

 This hypersthene-andesite mass is contemporaneous in the Lower 

 Marine Series; the mudstones can be seen dipping under it at a 

 gentle angle (9i°-10°) on its northern side, and they have prac- 

 tically the same dip at its western end, so that they, apparently, 

 have not been disturbed by the volcanic rock. The centre of erup- 

 tion must have been somewhere in the vicinity of Blair Duguid 

 Hill, and the activity here was doubtless responsible for some of 

 the blocks of andesite in the Allandale Conglomerate, as well as 

 for the tuft'aecous nature of the Harper's Hill Sandstone. The 

 hypersthene-andesite contains a great number of steamholes filled 

 with secondary material, and beautiful specimens of agate, chal- 

 cedony, etc., can be obtained. At the eastern end of the mass, near 

 the junction of two creeks in portion 152, Parish of Allandale, 

 masses of chert, up to about 18 inches in diameter, have been 

 floated up in the lava. This chert resembles very much that in 

 which Carboniferous fossils are found near Winder's Hill, and 



