Sinnott and Bartlett — Coniferous Woods. 279 



In addition to lignite, the clay at the Central High School 

 site provided a fine collection of charcoal fragments, which 

 had obviously been transported by wind or water from a forest 

 tire. These fragments were unquestionably carbonized before 

 they were buried, for they were associated with typical lignite 

 derived from the same kind of wood. It must, therefore, be 

 understood that the charcoal referred to in the following pages 

 is charcoal in the usual acceptation of the word, and not the 

 material sometimes called " carbonized wood " or " mineral 

 charcoal." 



The second locality where lignite and charcoal were collected 

 is about half a mile from the first. In the improvement of 

 Meridian Hill Park on 16th Street the well-known section at 

 that place has been re-exposed. On account of weathering, 

 the leaf impressions and lignite formerly collected there had 

 long been inaccessible. The lignite-bearing bed at Meridian 

 Hill is much more restricted than that at the Central High 

 School site, but is in a way more interesting because of the 

 fact that the lignified wood appears not to have been trans- 

 ported, but rather to have been buried in situ. The same 

 layer which contains the lignite contains the leaf impressions 

 which have been reported by other writers from " 16th Street." 

 The Meridian Hill section on 16th Street opposite Crescent 

 Place is approximately as follows : 



"Lafayette." Red loam 1ft. 



Red gravel containing bowlders 5 ft. 



Red and yellow loam . . 8 ft. 



Coarse red gravel and bowlders, with 



iron crusts .. 8 ft. 



Patuxent. Lignitic clay with leaf impressions „ 3 ft. 



Green sandy clay 5 ft. exposed. 



A few feet further north, at the point where the lignite and 

 charcoal collections were made, the plant bed pinched out and 

 passed under a layer of ferrugineous arkosic sand, which 

 formed a layer three or four feet thick between the pinkish 

 clay plant bed and the overlying bowlder layer. The writer 

 has collected no satisfactory impressions at Meridian Hill 

 except foliage and cones of Arthrotaxopsis, but Berry (1. c.) 

 reports the following identifications : 



Onychiopsis psilotoides (Stokes & Webb) Ward. 

 Podozamites distantinervis Fontaine. 

 JVac/eiopsis angustifolia Fontaine. 

 Arthrotaxopsis grandis Fontaine. 



The plant bed is in places full of impressions which are 

 unquestionably referable to Nageiopsis, although they are very 

 badly preserved. Much charcoal may be found by careful 



