JAMES REID ON PARKA DECIPIENS. 1 25 
Myreton, and by Mr. Win, Graham, from Turin Hill, noar Forfar, 
and also upon specimens kindly presented by Mr. P. Macnair of 
Glasgow (all of which in essential particulars were the same). Some 
of the material from the shales of Myreton apparently indicated a 
high state of preservation, and from this the microscopic examination 
by Sir Wm. Dawson was made, which resulted in the discovery that 
Parka decipiens was a plant (allied to Pthtlariak) possessing a creeping 
rugose stem, linear leaves, and sporocarp, with contained spores and 
prothalli. The process by which this result was arrived at may be 
described as follows i —The rounded flattened discs of Parka^ when 
stripped from the matrix and examined under the microscope as 
opaque objects, in some of the best specimens, showed a hexagonal 
cellular areolation identical with the structure of extinct Pvotosalvinia. 
Some of the discs, on being boiled in nitric acid to remove the 
opaque outer coat, presented an inner transparent structure. This, 
upon being broken up in water, disclosed a mass of amber-coloured 
spores of two kinds, namely, macrospores and microspores. Prothalli 
in various stages of development were more sparingly obtained.* 
In this connection we quote an extract from the letter of a friend 
“In the latter part of 1892 we had the pleasure of being present at 
an examination of some discs of Parka decipiens. In one case 
which was placed for a short time in nitric acid—we found under the 
microscope a beautiful semi-transparent body, showing perfect hexa¬ 
gonal structure (extending from margin to margin of the disc) 
identical with the structure of the sporangia of recent Salvinia 
natansP 
(Signed) G. Soutar. 
J. Richardson. 
^Ve may state that, in addition to Parka decipiens.^ Psilophyton^ 
Zosterophyllum.^ Pachytheca.^ and certain seed-bodies occur in the 
Lower Old Red Sandstone of Forfarshire. These, however, do not 
come within the scope of the present paper. 
STEMS, LEAVES, AND SPORES OF PARKA DECIPIENS. 
In a recent review of Dawson and Penhallow’sf papers on Parka, 
Mr. Kidston remarks :—“ But in the absence of any knowledge of 
their organic union .... we have no evidence placed beyond 
reasonable doubt that the stems and leaves (?) with which Parka is 
associated are really referable to it.” ^ 
We find, however, in the paper under review, a stalked fruit cluster 
of Parka figured. And in Miller’s Old Red Sandstone a stalked fruit 
* Trans. Roy. Soc. Canada, 1891, pp. 6, 7, 15. + Trans. Roy. Soc. Canada, 1891. 
+ The Annls. Scot. N. History, 1893, P- 254 - 
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