Geohxjn oj Lih/Jolf. .V67 



<i The Lnwt'i' 'I'dSL-aiiiti' st-ries. 



h Tlif I'pper Tdscanite series. 



r Tlic Lower Dat-ite series (passing up iiitu a fia<.niitMitaI st-iies). 



(I 'I'lie Middle Dacite series. 



f Till' I'jipfr or Hyperstliene Daeite seiies. 



For the sake of economy in spaee. when referring to these series, 

 the aliDve letters — a, h. r. r/. and e are freiiuently used instead of 

 givinu t lie whole name. 



(I. Tlif Litiifi- Toxfdiiitr Srr/is. 



This is a eomplex series of lavas alternating.' with laminated for- 

 mations, which ouf^ht probably to be I'etjardeii as a l)anded effusive 

 rock. 



Field reldtioiit;. The sei'ies forms a rouj^fh are reaching from 

 Lilydale to Avithin a mile of Wandin. bounded on its north and 

 ■convex side by the alluvium and Silurians of tlie Yarra basin, and 

 embracing on its concave side the next series (/>) in the system. 

 It is best developed on the west liml). where it forms the surface 

 rock of the greater part of Lilydale, and also the prominent ridges 

 just outside of the town on the north-east. It also occurs in 

 small patches along the western edge of the system, even 

 as far south as Montrose. There are two small patches of it east 

 of Mooroolbark, one an inlier in tlie next series (h). and the othe;' 

 an outlier on the Silurians. It. therefore, had a wide distribution. 

 Owing, probably, to denudation, it becomes less conspicuous going 

 east from Lilydale, and occurs there only in discontinuous areas. 



Stratigraphical Relationship. — (i.) Its wide distribution, and its 

 invariable association with series 6, show that these two adjacent 

 series were co-extensive over a large area, (ii.) The chemical evi- 

 dence show that a and h are inseparable. The one must, therefore, 

 lie immediately, either above or below the other, (iii.) a is in many 

 cases immediately underlain by the Silurians, and h is visibly in 

 one place, and over a large area may be proved to be, overlain 

 immediately by the series c. Therefore, since a cannot lie above 6, 

 it must be below it. This conclusion is further supported by the 

 arrangement of vesicles in series a, in the lailway cutting behind 

 Lilydale, so as if continued to dip beneath the adjacent series, h. 

 This conclusion is corroborated also by the apparent superposition 

 of a high conical hill of series 6 on a low platform of series a, which 

 flanks the former on the north and west. 



Taking this evidence together, it seems safe to conclude that a 

 is older than h. 



N 



