PAEKA DECIPIBNS. 13 



Paeka Decipiens, No. T. — The structures about which the interest of this present 

 inquiry primarily centres, and those to which the name of Parka decipiens was in the first 

 instance assigned, are represented by rounded or oval discs in various states of preserva- 

 tion and variously aggregated. Frequently these discs consist of carbonaceous bodies, 

 which may be separated from the matrix and which show definite structure. At other 

 times they appear as mere impressions, the mass showing hexagonal depressions as pro- 

 duced by the closely aggregated bodies originally present. 



These discs are in a few cases scattered separately through the matrix, but they are 

 more commonly aggregated in oval masses of variable size, the whole sometimes present- 

 ing evidence of having had a special covering. A comparison of these masses shows tliat 

 there are difierences in point of size, which render it desirable to consider them as falling 

 in three distinct groups. 



Group A. — The masses inclvxded in this group are usually of more or less regular out- 

 line, oval in form and with regular discoid markings. They measure 6 to 11 mm. in 

 diameter. There are also similar bodies containing Parka discs, but somewhat smaller, 

 measuring 5 mm. in diameter. One of these is shown in fig. 3, from which it appears 

 obvious, as shown by the imperfectly rounded and massed Parka discs, that they are 

 imperfectly developed forms of the larger but otherwise similar bodies. 



Group B. — Tn this group may be included similar oval bodies bearing an abundance 

 0Î Parka discs, usually of regular and well-defined outline, and measuring about 13 X 20 

 mm. They are, therefore, decidedly larger than the preceding. These show occasional 

 evidence of an outer covering, but in no case have I seen a stem to which they are ter- 

 minal. They are associated with the bodies of the G-roup A, and therefore with the same 

 leaves and stems. The discs in these masses are risually carbonized, though they are 

 frequently represented by mere impressions. 



These bodies are common, and are found associated with the small stems, with the 

 narrow linear leaA^es, and with the empty sporocraps already described. In two cases 

 there was an apparent stem. (Plate I, fig. 5.) Whether this relation is accidental or 

 normal cannot be fully determined from our specimens. Also, as shown in the same 

 figure, there is very strong evidence that an outer coA^ering has been removed by pressure 

 from the main body, thus allowing the escape of all but five of the enclosed bodies, of 

 which only mere impressions can be seen. 



Group C. — This embraces nearly complete oval bodies of large dimensions and frag- 

 ments of masses evidently of the same or nearly the same size. They are all obviously 

 larger than those included in the preceding group. Taking the most complete specimen 

 as a representatiA^e, they are found to measure 3"5 X 5'3 cm. They are associated with 

 the large rugose stems, and, like them, the carbonaceous matter is wholly replaced by red 

 oxide of iron in the more complete specimens. The fragments show carbonized Parka 

 discs or else mere impressions. Plate I, fig. 4, shows a portion of a characteristic mass 

 with carbonized discs. Associated with these larger masses are the broad linear leaves 

 [Cofdailes), and also to some extent the narrow leaves. 



From the foregoing comparisons it would appear that we have to deal with bodies 

 of a similar nature structurally, but differing materially in point of size. It might be 

 suggested that such variation represents difierent conditions of maturity, but a little 



