diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index 7c3015e659..a3a2787a41 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -185,9 +185,8 @@ type subscription struct {
 // EventSystem creates subscriptions, processes events and broadcasts them to the
 // subscription which match the subscription criteria.
 type EventSystem struct {
-	backend  Backend
-	sys      *FilterSystem
-	lastHead *types.Header
+	backend Backend
+	sys     *FilterSystem
 
 	// Subscriptions
 	txsSub    event.Subscription // Subscription for new transaction event
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index 3cf71b80b4..013b9f7bc2 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -628,11 +628,3 @@ func TestPendingTxFilterDeadlock(t *testing.T) {
 		}
 	}
 }
-
-func flattenLogs(pl [][]*types.Log) []*types.Log {
-	var logs []*types.Log
-	for _, l := range pl {
-		logs = append(logs, l...)
-	}
-	return logs
-}