In addition to vegetative remains, fertile remains from ten plants, representing seven distinct taxa whose size and complexity are much greater than most contemporaneous fossils, are reported from late Ludlow (Ludfordian) sediments of Bathurst Island in Nunavut, Canada. Evidence for the age of these beds is gathered from stratigraphic relationships and index fossils including conodonts, graptolites, and brachiopods. Zosterophylls dominate the collection, some of which constitute the earliest record of fertile structures arranged in dense clusters and longitudinal rows along axes. Representatives include a plant that resembles Bathurstia, one species of Zosterophyllum, and two specimens that bear affinity to this genus. Distichophytum is also represented, as is a new zosterophyll named Macivera gracilis. The prevalence of sporangial clustering and reduced sporangial stalks in this flora leads to a discussion of the origins and significance of these morphological features. Following a review of some of the other Silurian floras, particularly the Baragwanathia-bearing Lower Plant Assemblage of Victoria, Australia, which also shows morphological advancement over the rhyniophytoid-dominated floras common to Laurussia, it is concluded that the Bathurst Island flora presents the best evidence to date of substantial morphological diversity, complexity, and stature of vascular land plants in this period.

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Abundant hexactinellid and lithistid sponges occur in Ludlow (Silurian) platform slope strata of the Cape Phillips Formation, Canadian Arctic Islands. The following are new: in the Anthaspidellidae Miller, 1889, rhodesispongia simplex n.gen and sp., Climacospongia snowblindella n.sp., and Climacospongia undulata n.sp.; in the Sphaerocladina Schrammen, 1910, Caryospongia tuberosa n.sp.; in the Hexactinellida Schmidt, 1870 Malumispongium? cornwallisi n.sp., of the monospecific superfamily Malumispongium Rigby, 1967. Other previously described sponges recognized in the study assemblage include Hindia sphaeroidalis Duncan, 1879 and Caryospongia juglans Rauff, 1894. These occur in association with abundant Archaeoscyphia sp. in thin, laterally extensive lithistid sponge biostromes which throve on platform slope sediments during the Late Silurian. Based on the dominant dendroclone forms in the skeletons of these and other genera, Anthaspidellidae can be divided informally into two groups: (i) the polyclonids, possessing complex skeletons built of variable dendroclones types, including I-, X-, and Y-shape dendroclones, and accessory spicules, including rhizoclones, chiastoclones, and monactines; and (ii) the monoclonids, possessing simpler parenchymal canal systems and skeletons constructed mainly of I-shaped (amphiarborescent) dendroclones and lacking accessory spicules. The classification, based chiefly on skeletal architecture, suggests two main evolutionary trends in the family. The monoclonids generally maintained structural simplicity, inherited from the probable ancestral monactinellid, whereas the polyclonids evolved a varied and complex skeletal architecture that was more successful.

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The Phanerozoic bedrock geology of Vendom Fiord map area (NTS 49D) features unmetamorphosed sedimentary rocks of mostly Lower Cambrian to Upper Devonian and Paleogene ages exposed within 1) the central Ellesmere Fold Belt, 2) an intensely faulted portion of the Arctic Platform, and 3) the an intervening regional synclinorium (Schei Syncline) which can be traced from central Ellesmere Island to Grinnell Peninsula on western Devon Island. The Paleozoic succession thickens westward from a feather edge where the Lower Cambrian lies nonconformably on Paleoproterozic granulites of the Inglefield Mobile belt (1.98 to 1.75 Ga) to a thickness exceeding 10 km under the western map edge. Prominent depositional features of the lower Paleozoic include shelf to basin facies changes involving nine formations of Upper Ordovician to Lower Devonian ages, biostromal carbonate buildups of Silurian age containing migrated hydrocarbons, important unconformities in Pragian and Emsian strata that provide a late Caledonian uplift history for south eastern Ellesmere Island, and Middle to Upper Devonian foreland clastic formations that are the depositional record of the Ellesmerian Orogeny. The Schei Syncline and Central Ellesmere Fold Belt are Devonian-Early Carboniferous tectonic features produced during the Ellesmerian deformation. Subsequent planation has formed a regional angular unconformity with Upper Paleocene to Middle Eocene Eureka Sound Group sediments deposited above this surface and preserved now in numerous widely scattered fault-bounded outliers. These strata are the depositional response to phases of compressive and strike-slip deformation during the Eurekan Orogeny, also related to more distant events including sea floor spreading in Baffin Bay and the plate motions of Greenland. Commercially significant coal resources are exposed in Eocene strata near the south shore of Stenkul Fiord.