Those attending G.F.D. 1984 were introduced to the novel topic of Geological Fluid Mechanics by our Principal Lecturer, Herbert Huppert. He presented his studies both as a discipline with recent fascinating successes, and as a challenge to his listeners to further isolate mathematically tractable examples of these multi-component flows. Geological Fluid Mechanics has been the responsible process for the formation and modification of most of the geological objects studied today. The dynamics of fluid mixtures in magma chambers, the changing fluid boundary conditions and composition during selective crystallization of parts of the melt, and the separation of fluid fractions of different density and viscosity all represent areas in which quantitative theories are currently being tested. However, equally many areas, including convection mechanisms in the Earth's core and quantitative predictions for upper mantle motion, resist simplistic modeling.

The explosive growth of dynamical system theory stem in large part from the realization that it is applicable to many natural phenomena. Indeed, much of the theoretical dvelopment has been sparked by numerical and laboratory experiments which exhibit ordered sequences of behavior that call for a general framework of interpretation. Five lectures exposed us to elementaty examples of bifurcation and chaos, to symmetry breaking, normal forms and temporal and spatial disorder, as well as to pertinent fluid mechanical and astrophysical phenomena. In addition are the development with an elegant summary of different types of intermittency; Seminars on phase instability and turbulence as an extension of the lecture series; and the fascinating correspondence between the frequencies observed in one recent fluid mechanics experiments and results from number theory relating the Fibonacci series to the golden mean.

The explosive growth of dynamical system theory stem in large part from the realization that it is applicable to many natural phenomena. Indeed, much of the theoretical dvelopment has been sparked by numerical and laboratory experiments which exhibit ordered sequences of behavior that call for a general framework of interpretation. Five lectures exposed us to elementaty examples of bifurcation and chaos, to symmetry breaking, normal forms and temporal and spatial disorder, as well as to pertinent fluid mechanical and astrophysical phenomena. In addition are the development with an elegant summary of different types of intermittency; Seminars on phase instability and turbulence as an extension of the lecture series; and the fascinating correspondence between the frequencies observed in one recent fluid mechanics experiments and results from number theory relating the Fibonacci series to the golden mean.

Four principal lecturers shared the task of presenting the subject 'Coherent Features in Geophysical Flows' to the participants of the twenty-second geophysical fluid dynamics summer program. Glenn Flierl introduced the topic and the Kortweg-de Vries equation via a model of finite amplitude motions on the beta plane. He extended the analysis to more complex flows in the ocean and the atmosphere and in the process treated motions of very large amplitude. Larry Rdekopp's three lectures summarized an extensive body of the mathematical literature on coherent features. Andrew Ingersoll focussed on the many facinating features in Jupiter's atmosphere. Joseph Keller supplemented an interesting summary of laboratory observations with suggestive models for treating the flows.