diff --git a/src/trace/implementations/ord.rs b/src/trace/implementations/ord.rs
index a8cea33f6..e0a85eff2 100644
--- a/src/trace/implementations/ord.rs
+++ b/src/trace/implementations/ord.rs
@@ -85,7 +85,7 @@ pub trait Layout {
 }
 
 /// A layout that uses vectors
-pub struct Vector<U: Update, O: OrdOffset> {
+pub struct Vector<U: Update, O: OrdOffset = usize> {
     phantom: std::marker::PhantomData<(U, O)>,
 }
 
@@ -99,7 +99,7 @@ impl<U: Update+Clone, O: OrdOffset> Layout for Vector<U, O> {
 }
 
 /// A layout based on timely stacks
-pub struct TStack<U: Update, O: OrdOffset> {
+pub struct TStack<U: Update, O: OrdOffset = usize> {
     phantom: std::marker::PhantomData<(U, O)>,
 }
 
diff --git a/tests/trace.rs b/tests/trace.rs
index d00c4497e..1d830e094 100644
--- a/tests/trace.rs
+++ b/tests/trace.rs
@@ -6,16 +6,16 @@ use std::rc::Rc;
 use timely::dataflow::operators::generic::OperatorInfo;
 use timely::progress::{Antichain, frontier::AntichainRef};
 
-use differential_dataflow::trace::implementations::ord::OrdValBatch;
+use differential_dataflow::trace::implementations::ord::{OrdValBatch, Vector};
 use differential_dataflow::trace::{Trace, TraceReader, Batch, Batcher};
 use differential_dataflow::trace::cursor::Cursor;
 use differential_dataflow::trace::implementations::spine_fueled::Spine;
 
-pub type OrdValSpine<K, V, T, R> = Spine<Rc<OrdValBatch<K, V, T, R>>>;
+pub type OrdValSpine<K, V, T, R> = Spine<Rc<OrdValBatch<Vector<((K, V), T, R)>>>>;
 
 type IntegerTrace = OrdValSpine<u64, u64, usize, i64>;
 
-fn get_trace() -> Spine<Rc<OrdValBatch<u64, u64, usize, i64>>> {
+fn get_trace() -> Spine<Rc<OrdValBatch<Vector<((u64, u64), usize, i64)>>>> {
     let op_info = OperatorInfo::new(0, 0, &[]);
     let mut trace = IntegerTrace::new(op_info, None, None);
     {