| Area 1: The Boundary Lake Member consists of tidal flat and lagoonal limestone and dolomites. |
| Sedimentary structures such as horizontal bedding, ripple bedding and rhythmic bedding are well developed, indicating a lagoonal environment. |
| Many lagoonal lakes occur along low coastlines. |
| In all these lagoonal settlements the characteristic plan, still detectable in the street patterns, was dominated by a navigable channel from which side channels branched at intervals. |
| The field is in foreslope, reef margin and reef interior lagoonal facies of an atoll-type reef which built up to 150 metres above a regional limestone platform. |
| Thus, an atoll or annular reef may develop along the rim around the low-lying central region, which becomes a lagoon, and coral knolls grow on former pinnacles in the lagoonal area. |
