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Parha decipiens. Notes on specimens of collections, etc. — (Continued.) 

 Part II. — Microscopical and Botanical Results. 



(With Plate I) 



By D. P. Penhallow, B.Sc. 



Early iu the winter of 1890-91, Sir William Dawson placed iu my hands certain 

 specimens of Parka decipiens, with the request that I should make a microscopical examin- 

 tion of it. The material was originally obtained from Mr. James Reid of Blairgowrie, 

 Scotland, and consisted of gray and micaceous sandstone bearing impressions of Parka, 

 together with a number of the Parka discs which had been boiled out in nitric acid. 

 After careful examination and comparison, the conclusion was reached that Parka was 

 an aquatic rhizocarp, probably allied to Pilularia. Since then a large amount of corre- 

 spondence on the subject has passed between Mr. Reid, Mr. Graham and Sir William 

 Dawson, and we have also received from the first named gentleman a large amount of fresh 

 material, together with the results of more recent observations made at the various local- 

 ities where Parka is found in abundance. Some of this additional material throws light 

 upon hitherto obscure points, while many of the suggestions offered by Mr. Reid and Mr. 

 Grraham are of considerable importance as bearing upon the views entertained by Sir 

 William Dawson and myself. 



In consideration of these facts, it has seemed desirable to carefully review the whole 

 subject from the double standpoint of the data furnished by the two gentlemen referred 

 to and the evidence of the specimens as brought under my own insiiection. It seems the 

 more important to do this since the question of the animal origin of these fossils, raised 

 some years since, has not, up to the present time, been wholly disposed of. 



The origin of the specimens, their geology and history have been fully considered by 

 Sir William Dawson in the preceding pages, and it therefore devolves upon me to con- 

 sider them botanically, upon the basis of microscopical examination of the various parts. 



Preliminary to such an enquiry, it has been found desirable to classify the material 

 in a general way, without reference to locality. All the specimens so far examined thus 

 naturally fall into the following grovips : 



1. Rugose stems, in which the organic matter has been wholly replaced by red 

 oxide of iron. Many fragments of these show little iu detail, though all agree in general 

 characteristics. The most perfect is 36 cm. long, 4.5 cm. wide at the lower end and 3 cm. 

 broad at the upper end. Three branches, alternate and opposite (?), are distant from one 



Sec. IV, 1891. 2. 



