Maryland Geological Survey 235 



feature of most of these ferns is rare in the other fern-families, and when 

 present is usually a variable and not a characteristic habit/ 



The genus, which is obviously unlike any previously known, is named 

 in honor of Dr. P. H. Knowlton, as a slight appreciation of the value 

 of his contributions to our knowledge of fossil plants. As KnowUonia 

 has already been used by Salisbury for a member of the Ranunculacea^, 

 the present genus may be known as KnowUonella. The Matoniacese, of 

 which but two existing species are known, from a very restricted area in 

 the East Indies, are of considerable importance in the Mesozoic and 

 enjoyed a wide range. The occurrence of the existing species is shown on 

 the accompanying sketch map, as well as the known occurrences of fossil 

 representatives. These have been obtained by plotting the recorded oc- 

 currences of Laccopteris Presl, Matomdium Schenk, Phlehopteris Bron- 

 gniart, Microdictyon Saporta, Outhiera Presl, Carolopteris Debey and 

 Ettinghausen, and Marzaria Zigno, and may in some instances represent 

 incorrect identiiications. It will be seen that this family, while ap- 

 parently present in the Arctic region and in North America, was a prom- 

 inent element in European Mesozoic floras from the Upper Triassic 

 through the Jurassic and Lower Cretaceous, and continued to be repre- 

 sented well into the Upper Cretaceous. Some of the European material 

 is very satisfactory, and has been the basis for a considerable body of 

 literature. 



Knowltonella Maxoni sp. nov. 



Plates XXV, XXVI, XXVII 



Description. — Fronds as described for the genus {supra). Pinnules 

 of normal form varying in size from 0.6 cm. in length by 1.5 mm. to 



^ For a discussion of the living Gleiclieniaceae see Underwood, A prelimin- 

 ary review of the North American Gleicheniaceae, Bull. Torrey Bot. Club, 

 vol. xxxiv, 1907, pp. 243-262. 



For a comparison of the living and fossil Mationiaceae see Seward, On the 

 structure and affinities of Matonia pectinata R. Br., with notes on the geo- 

 logical history of the Matonineae, Phil. Trans. Roy. Soc, Lond., vol. <;xci, 

 189^, pp. 171-209, pis. xvii-xx. 



