Looking back over a century of geoscience research in the Cordillera is both an inspiring and a humbling exercise. So much has been learned that could not have been imagined in 1899! Other contributions to this volume discuss some of the classic papers in various fields that have led the way to fundamental new insights. In this opening chapter, I prefer to highlight the largely unsung but crucial contributions to the overall research effort that have been made by thousands of faces in the crowd laboring steadily outside the limelight to advance our understanding of Cordilleran geoscience. It is easy to forget that the pacesetting perceptions of the giants among us would be impossible without the information gained, day to day, by uncelebrated colleagues who work assiduously, by their own best lights, to dispel the scientific darkness bit by bit. In our admiration for intellectual leaders, we should always remember that science is the most supremely collegial and collaborative of all human endeavors. They also make their marks who never win an award, but must be content with the plaudits of their own consciences. <...>

The geometry and distribution of the clastic dv s.es of the Ono district. North Sacramento Valley are examined within stream sections. Five traverses along dry stream beds provide good exposure allowing the spacing, thickness and geometry of the dykes to be reorded. The spatial and thickness distribution of the dykes are considered using cumulative frequency plots, allowing a visual estimation of a best lit distribution. Dyke thickness conforms best to a log-normal distribution. There is also a characteristic minimum dyke thickness in a traverse and this is attributed lo the minimum aperture thai a fluid with sand clasts is able to exploit. Dyke spacing, however, shows a good correlation with a power-law distribution for four traverses, suggesting thai there is a mechanistic control on the spatial dislribulion. Plolting dyke thickness against minimum dyke spacing reveals that thin dykes do not generally intrude in isolation. I'nlike veins and igneous dykes, elastic dykes continue lo provide preferential pathways for fluid flow, subsequent lo their intrusion, thus inhibiting intrusion in the area surrounding a pre-existing dyke. Acombination of this process and dyke branching provides the best model for the observed spatial and thickness distribution of clastic dykes seen in the Ono district. California.