PARKA DECIPIENS. 5 



The specimens sent to me by Mr. Eeid are from various parts of the Devonian belt of 

 Perth and Forfar, ranging- from Callander in the south-west to Eescobie in the north-east 

 as well as some slabs from the Caithness flags, Avhich Murchison regarded as of the same 

 age with the Arbroath flags. All the specimens hold fossil plants of similar kinds ; but 

 so far as Parka is concerned the most important are from Myreton quarries, near Dundee 

 and from Eescobie ; the latter I believe from the collections of Mr. W. Graham of that 

 place. 



The specimens from Myreton quarries are in part gray flags containing carbonized 

 plants ; in part dark gray, hard, ai'euaceous shale, with flattened rugose stems, one as 

 much as four inches in diameter, branchlets of Psilophyton, linear leaves and patches of 

 Parka. These last are carbonized and often well preserved. They have aiforded the best 

 specimens for microscopic examination. 



The specimens from Eescobie are gray and sometimes micaceous flaggy sandstone, 

 similar to the last, with fragments of plants and patches of Parka, the whole flattened and 

 carbonized or replaced by red oxide of iron. The plant remains consist of thick rugose 

 stems, sometimes branching, and elongated leaves {Cordaites angus(ifolia), and fragments of 

 Psilophyton. 



Some specimens from Blairgowrie, consisting of similar gray flaggy sandstones, con- 

 tain many fragments of plants, also certain seed-like and fruit-like bodies, one of which 

 has the markings of Parka. 



The only animal remains detected in the collection were a few fragments which may 

 have belonged to large Merostomatous crustaceans or to placogauoid fishes. Some of these 

 present an irregular or scaly reticulation, which might at first sight be confounded with 

 Parka, but is readily distinguished on closer inspection. 



The specimens of Parka decipiens are scattered over the surfaces of the slabs and inter- 

 mixed with and sometimes apparently attached to the fragments of plants, especially the 

 branches of the rugose stems above referred to. They are of various sizes, from half an 

 inch to nearly two inches in diameter, and either rounded or of reniform or irregular shapes. 

 They consist of aggregations of flattened circular or hexagonal bodies, all nearly of the 

 same size, so that the smaller patches contain few granules and the larger a greater number. 

 In many cases there are evident remains of a membranous indusium or covering, and 

 several are so situated at the ends of stems as to appear to be connected with them. The 

 covering was either originally incomplete or liable to open by dehiscence or decay, and in 

 some cases it has disappeared altogether. In the carbonaceous specimens from Myreton the 

 iudividi;al circular granules can be easily separated from the stone as thin pellicles of 

 carbon, and can be mounted for microscopic study, though they are perfectly opaque. The 

 appearance of hexagonal meshes would seem to be produced either by mutual pressure in 

 flattening or by the compression between them of some soft substance filling their inter- 

 stices. They were probably originally globular, but must have been soft and com- 

 pressible, and probably only in one layer, and not in a globular mass or berry-like form. 

 The apparent iudiisium may either have been a sac-like covering or a frond to which a 

 layer of globules was attached. The greater part of the flattened discs are, to the naked 

 eye, perfectly smooth ; but a few show slight prominences or pustules, which may indi- 

 cate small and dense globules enclosed in the individual disc or granule. 



"With reference to the disputed question as to the nature of these bodies, it is evident 



