ESTHERIA MINUTA, VAR. BRODIEANA. 75 



The late Mr. Patrick Duff favoured me (in 1860) with some specimens from his 

 cabinet, collected probably many years ago, which consist of a hardish, greenish-grey, 

 fine-grained, sandy, calcareo-argillaceous shale, crowded with thin, light-brown, and dark- 

 brown Estherics, preserving but very little of their original convexity. These have 

 here and there a reticulate ornament (such as seen in PL II, fig. 10), but often appear to 

 be smooth. 



Mr. S. H. Beckles, F.R.S., E.G.S., kindly procured for me, in 1861, a quantity 

 of the Estherian shales, from Linksfield ; these are also greenish-grey, calcareo-argil- 

 laceous shales, but are soft, contain fewer Esther ice (which are thin, flattened, and of a light- 

 brown colour), and are associated with similar shales full of Cypridce. A few Esthcrice are 

 sometimes scattered among the Cypridce. The specimens here have often a boldly 

 reticulate ornament, passing (towards the ventral edge) into short transverse bars (such 

 as seen in the North American Estherice, PI. II, fig. 37). 



Lastly, Mr. Charles Moore, E.G.S., has lent me some specimens of green clay from 

 Linksfield, crowded with dark-brown, crushed Estherice, having a distinct reticulate orna- 

 ment (PI. II, figs. 9—11). 



The Linksfield shales of Morayshire have long been known from the careful descrip- 

 tion of them published by the late Mr. Patrick Duff, of Elgin, in his ' Sketch of the 

 Geology of Moray,' Elgin, 8vo, 1842. 



At first they were collocated with the Wealden or rather the Purbeck beds, by Dr. J. 

 Malcolmson (see Mr. Duff's ' Geol. Moray/ p. 19, and 'Quart. Journ. Geol. Soc.,' vol. 

 xv, pi. xi, fig. 2) ; Mr. Beckles 1 also, in 1858, was struck with the close lithological 

 resemblance of the Linksfield shales to the Purbeck beds. Prof. Morris has considered 

 these shales to represent a freshwater deposit of the Lower Oolite period (like the Brora 

 beds), as is evident by his referring the Linksfield fossils (in his ' Catal. Brit. Fossils ') 

 to the Great Oolite. In 1860 Mr. Charles Moore ('Quarterly Journal Geological 

 Society,' vol. xvi, p. 445) recognised a similarity of appearance between the shales 

 and thin limestone bands at Linksfield and those of the Bone-bed (or Rhaetic) series 

 (at the base of the Lias) at Pylle Hill, near Bristol, at Aust Passage and Penarth, 

 on the Severn, and at the Uphill cutting on the Great Western Railway, and more 

 particularly in the presence of beds at Linksfield representing the " White Lias," the 

 " Gotham Marble," the "Bone-bed," and the gypseous clay-bands of the Rhaetic forma- 

 tion in the South of England. The fossils also appeared to him to support this corre- 

 lation. Lastly, the Rev. W. S. Symonds, writing in 1860, refers to "the probable 

 Liassic and Triassic character of the shales at Linksfield " (' Quart. Journ. Geol. Soc./ 

 vol. xvi, p. 459. See also ' Edinb. New Phil. Journ./ New Ser., 1860, vol. xiii, 

 p. 99). 



1 My friend Mr. Beckles kindly went to considerable expense (in 18o'l) to obtain for me a large 

 series of these fossiliferons shales and limestones, especially those rich with Ci/jvidce and Estherice. 



