F or the past two years, members of the biology faculty at Pace College have sought their green pastures and burbling brooks among the construction sites and garbage dumps of New York City. They have been teaching a course in ecology for city high school teachers. Many colleges offer such courses; generally, though, these colleges are situated in bucolic surroundings with ready access to unpolluted rivers, beaches, fields, and forests. The location of Pace, in lower Manhattan-the epitome of the urban environment-is not by any means a typical location for a field course. Our goals in presenting it had to be somewhat different. We wished to determine the kinds of organisms that manage to gain a toehold in the adverse world of concrete and exhaust fumes. And, perhaps more importantly, we wished to enable high school biology teachers in city schools to use more material from the students' immediate environment. With the increasing concern over degradation of the environment and the growing emphasis on ecology in high school biology, city teachers would seem to have a difficult task in providing practical ecological material for their students to observe and experiment with. We aimed to show that this difficulty may readily be overcome-that even in the apparent barrenness of the city a great variety of material is available for demonstration. But there apparently has been very little study of this type of environment: the literature is virtually nonexistent. Therefore the course has been a challenge to instructors and students alike. As for need: with the increasing extension of the urban environment, more and more children will spend their entire lives within the city, and much of biology as presently taught will have little relevance for them. Surely, we reasoned, it would be more satisfactory to teach aspects of biology which would open their eyes to the complexities of the urban ecosystem of which their own lives are a part. The course, funded by the National Science Foundation, consists of a three-week summer portion followed by six days of work (demonstrating seasonal changes) scattered through the Saturdays of the year following. During the first summer week some basic ecology is reviewed in lectures and seminars, aided by field trips to the pseudo-urban en-