3i6 Hawell : An Oolitic Plant Bed in North Cleveland. 



Some of these have been recorded both from the Lower 

 Estuarine plant bed of the Yorkshire coast and from the plant 

 bed of the Middle Estuarines, viz. : — Eqiiisetites coliwinaris, 

 Tceniopteris vittata, Willianisonia pecteti. It appears as though 

 the g-eneral facies of the Marske plants had more in common 

 with that of the flora of the Middle Estuarines of Gristhorpe 

 and Cloug-hton than with that of the plants recorded from the 

 Lower Estuarine Series of Hayburn Wyke, Staintondale, Salt- 

 wick, and Whitby. I believe the only two species in my list 

 which are named in Mr. Fox-Strangway's list from the Lower 

 Estuarines, and are not in the Middle Estuarine List, are 

 Oi)zamites parallelus and Williamsonia gigas, while in his list 

 from the Middle Estuarine Beds occur the names of Sagenopteris 

 Ptiillipsi, Nilssonia conipta, N. mediana, N. teiminervis, Tceni- 

 opteris major, and Ginkgo digitata, none of which are recorded 

 from the Lower Estuarines. I cannot find that Nilssonia has 

 been recorded at all from the Lower Estuarine Series of York- 

 shire, and specimens are extremely plentiful at Marske. 



This question needs much more investigation than I have so 

 far been able to give to it, and it is possible that I may he able 

 to trace a succession of plant horizons at Marske. I am 

 inclined to believe, however, that the same plants were living in 

 the neighbourhood throughout the Estuarine period, and that 

 further investigation will show that most of the plants which 

 have so far been found only in the upper or the middle division 

 are really common to both. I was disposed to think that the 

 Marske plant bed was probably below the horizon of the EUer- 

 beck marine bed, which has not been traced on the Upleatham 

 outlier, and almost certainly of the age of the Lower Estuarines, 

 but at present I have an open mind on the subject, and it may 

 ultimately seem probable — for I doubt whether we can prove 

 one thing or another — that it was contemporaneous with both. 

 I hope to be able to trace this bed, or at least beds more or 

 less contemporaneous with it, over other portions of the 

 Cleveland moorland area. Plants occur in other localities 

 apparently on much the same horizon, and some of these 

 localities I propose to visit soon and try to work out a probable 

 theory as to the conditions which prevailed when these plants 

 were deposited, apparently in quiet lagoons or channels, 

 separated temporarily from the neighbouring sea where tides 

 and currents made perpetual motion. 



The splendid state of preservation of many of the Marske 

 plants encourages me to hope that evidence of considerable 



Naturalist, 



